Starting with the actual game mapping, OfficerTJHooker has an excellent one a few posts back. Using this, along with Trans Agg to translate doors names should be enough. Might need minor trial and error to piece the names to their destinations. Also, as a minor correction, as of right now, the Hollow Tree "does" in fact have a repair spot that may have been added in a later patch.
However to clarify some bonus maps, once unlocked, they can be accessed though the memories menu (The crystal icon) within the system menu (The D key opens it, might need to press Q and W to switch windows to it.) I have found 4 so far, being Dame Verte, Banshee, Automation, and La Belle.
In the maps themselves, there are 4 switches, top left activates "over-sensitive" which you need to have to view their respective CG's. The middle option sets if the mobs are allowed to spawn adds. Top option allows it, bottom one deactivates it. (So no flower monsters from Dame, no shadows from Banshee, ect.)Top right removes "over-sensitive", and the bottom magic circle begins spawning. They spawn one at a time and never stop even after you either kill them or they leave after being "satisfied". Only way to leave these maps is via F12, or pressing the Z key after the option to "give up" appears in the bottom right of the screen.
As for the actual unlocking of the bonus maps, no idea, didn't really pay attention to their exact appearance times.
Next, regarding costumes, most are found after finding a boss, or in a chest at certain safe maps. Once you've found them, they will begin to show up at random in any map.
Two particular costumes can only be crafted however, the Cardinal Robe, and the infamous Stray Cat, firstly, unless I'm mistaken, they both cap at 2 sockets, so beware if your running a 3-4 socket build and rely on them.
The Cardinal Robe you will need to craft using a Sister Essence and Sister's Robe, the essence you will obtain after beating the game, and resetting. The new area you start from will have a chest containing it. (You will also be allowed to loot freely from the donation box. But, only while your in that new map. After you leave, you'll be thrown back into the forest starting zone, and the chapel box will still require item swapping.) If you plan to use the robe, make sure you firstly use a 3 socket sister's robe (And use an alchemist box to empty the sockets safely if necessary). As it will retain the sockets of the robe, minus one. After that, head to the dwarf, cough up 4000(!!) ect and you have your new robe. It will keep the +'ing you've already made to it, but wipe the essence from it, so make sure you remove em first.
The infamous Stray Cat is whole different ballpark. Firstly, if you plan to go through the game sex or defeat free (though you will keep your virginity), you will need to pass this one up, as it requires some intimate time with La Belle to obtain the Lycanthrope debuff. You will need to pack your usual items (potions, food, repairs ect.) However also make sure to have at least two scrolls of punishment, a scroll of bestseller (reveals the map) and a scroll of master-ninja (shows monster locations on map). Head to the city and proceed like normal until you reach floors 5+ and start checking every room for a Belle appearance. When you do find her, things get both tricky and luck based. Start checking every room and killing everything short of Belle herself, abusing your bestseller and ninja scrolls to track mobs and punishment to clear out brothels or other threats. While looking around, try to find both a Clearance trap (for safe escape) and Southern Sunshine trap (Yellow blotch, causes the feel-revolution ailment). Feel-revolution will let you remove clothes freely when active. Not required, but saves a lot of durability when its just you and her. When everything is taken care of, proceed to let Belle have her way with you until you receive the debuff, which in turn you can either, kill her or run away (or stay with her a bit longer). Getting the debuff is not 100% and you might need to F12 and try again (Or save scum your auto save, whatever floats your boat). When you do get it, you will need to go to the doctor and get the ailment removed, which in turn, you will get the animal essence. If you use this with the Gothic Bustier and 3000(!) ect in the same way as the Cardinal's you'll have your stray cat outfit.
Finally, I'll go over a few of the more dangerous monsters you may run into. (Sadly I don't remember all the spawn locations for them.)
#006 Black Dog-(Flies, blue with a yellow mane)-Likes to buff its AGI first thing, and spam a knock back whirlwind and lightning spell until it moves into range. When it gets low on health, will activate an electro shield that damages you when you attack it (Unless its a killing blow). The shield does a lot of durability damage, so I would try to finish it off with harder hitting moves, or use a wand of norojan-horse (Swaps status effects) to steal its shield and AGI buff and finish it off.
#012 Cheval de Batiar-(Green Horse head, Lord of the underground waterway)-Will spawn abyss toads every so often, and hits with low-medium damage water attacks. Clear out the toads asap as their potential intoxication effect its more dangerous then the boss in his entirety. If you do get intoxicated, make sure your holy water stack is up, as you may need to use them on recuperation to remove passion beat. Otherwise, the boss himself doesn't have anything too special besides water spells to watch out for. (Or maybe I fought him too late and found him to die faster then his novelist.)
#017 el Cuelebre-(Blue-green Zebra Dragon)-Considering how early you can find one of these makes it very threatening. Flies and moves fairly quick into melee range and will do a lot of damage quickly, try to shoot it down ASAP. Blinding it with holy water, or paralyzing it from redemption may help you keep it at bay. A wand of NEKO (Wind based knock-back) will also push it back a long way if you pick one up.
#018 Gargoyle-(Big grey yellow eyed beast)-Will burn through its entire MP pool with water gun before moving into melee range to finish you off. Water gun causes knock-back, and makes it very difficult to get close, use Sword's acute and stinger "if possible" to move into range. Make sure your ready to heal if you do get pelted badly. High AC and resist makes this a long fight.
#021 Dragger-(Giant Cyclops)-Big and slow, but will drop your AGI to help it move closer. Fight it at a distance and use redemption to paralyze it. If it does get close, use Holy Water to blind it, but expect some very painful hits. Thunder works well.
#024 Black Hand-(Blue cape, black hat, mask)-Uses poltergeist on sight, which can drag you from safe spots to open areas and even can inflict knockdown. Be ready to use movement abilities to move back into safe zones if this happens. Otherwise casts painful spells. (Heck, all spell casters are painful, just some more then others.)
#025 Initiate-(Black cloak, red eyes, rare)-Only rarely spawns in the city (maybe crypt too?), but doesn't make it any less of a threat. Spawns two Minions which he will immediately buff with STR up. Getting hit by these can deal upwards to 70+ damage, so be very careful. They also cannot be permanently killed unless you use turn-undead skill like redemption or punishment scrolls. The initiate himself will use damaging magic as well, so be ready for an annoying fight.
#028 The Wild Hunt-(Tall, wield a black sword, Lord of the forest)-You probably won't see this guy unless your on a return trip or going nuts and doing a forest to city jump. When you do, expect a nasty fight, summons a combination of melee and ranged hunting blades, and deals rather painful damage himself, and occasionally puts up a electro shield to make things worse. A lunatic scroll can turn the blades against each other which can help clear out the riot of mobs (Additionally as a general tip, if a mob kills another mob, they actually can, and will level up, while this makes them more threatening, their exp values rise greatly, making it a strangely effective way to level in safer areas.) If your on a return trip, this guy shouldn't be too difficult, however if your still early on, better off running for the nearest exit or guidance.
#031 Durahan-(Blue, headless wields a lance, Lord of the Graveyard)-The current final boss of the game. I don't know the exact details, but if you've fought and killed the four other lords, and visited each of the maps, he should show up in the 10+ search levels of the graveyard. By this point in time, you've likely fought all kinds of situations and are quite well prepared, expect a nasty fight. With a wide ice aoe that inflicts frost bite, damaging melee moves with a 2 square step-back, you'll have a hard enough time staying alive, let alone doing damage. He resist everything short of bashing damage and holy, so despite his movements guns aren't gonna deal much. Pack some elixirs, punishment scrolls, and drop everything you have, and he'll go down eventually.
#034 Ankou-(Carries a scythe, looks like death)-When I first saw this mob, I thought it was an auto game-over for going too deep in the forest search levels too early. Though considering he can be seen so early makes him just that. Summons two phantoms that will do their best to surround and strip you. The phantoms turn invisible but when they move into melee range, you can actually find them by holding the Q key and turning around. If they are close, you'll get the message "There is someone here" and you'll hit them if you swing. Ankou himself attacks in a wide 2x3 square in front of himself. Often cleaves his own allies, but can cause silence so be very careful.
#035 La Danse Macabre-(Skeleton in a suit)-The infamous dodging skeleton. With his high evade, hit rate, special dodging skills, poison, and blindness make this guy a literal ninja. You can either get on his level, stack the same stats and watch a single attack move you 4 squares back and forth, and do 15 actions between the two of you. Or attack in with unavoidable attacks such as wands, redemption, and holy water. Stuns and paralyze will cripple his evasion as well.
#037 Ghoul-(Big grey winged demon)-By himself he is just an above average melee attacker, however when he does get close, he likes to spawn 4 Decades (Zombies) to surround you. The zombies will strip and poison you so it can cause the situation to turn sour very quickly. His hp isn't the highest, so if your damage is good, you can kill him before he even summons sometimes.
#041 Jack in Iron-(Green Steam bot)-*clatter clatter*. If you see your chat box fill up with this message, it means he is near. He starts out invisible and roams only the hallways, so regardless of his size, he's still a stealthy bugger. If you do encounter him, be careful, as he hits very very hard. However with a measly 5 AGI, 2 Evade, 95 Hit, and 15 Resist, you can murder him very easily with heavy magic or high evasion/agility characters. (I've swung for a whopping 3 hits in one turn on this guy.) He also has the secret ability to screw up Trans Agg and make door translating a nightmare due to his clatter text.
#044 Incubator-(Squid!)-This. Thing. Sucks. For early game characters, this guy will murder your durability with his powered acid breath. If you do see him, try to lure him to an open room, and fight him with some space. If you see him charge up his breath. You can either strafe away diagonally forcing his breath to miss (Since your at an angle that he can't line up with) or use angelic halow and jump behind him, as power breath has even lower priority then halow's already low priority. (He will shoot the breath on your original location instead of your jumped location, there are mechanics as to why he can't turn around and how priority and turns work, but I'll save on the headaches unless someone really wants to know.)
#045 Red Ram-(Exactly as sounds)-He hurts, a lot. Sticks to melee, however deals a considerable amount of damage, and also swings with a fire follow up that cannot be dodged. Try to attack from a distance, but beware as he resists bullets. He won't let up until you either kill him, or he's literally ramming your rear.
#046 Black Goat-(Incarnate of terror and death)-My absolute most hated enemy in the game. Will fry you with about 60 points of magic damage a turn with a double cast. And as soon as your in melee range, will back-step about 3 squares and continue his BBQ. If you have a witch's scalpel (Wand that causes silence). Use it, and kill with extreme prejudice. This thing has nearly killed me more times then I'd like to count.
#047 Minos Daemon-(Green Horned Minotaur, Lord of the Crypt)-Depending on your build, this guy might be very very easy, or very very hard. One of the hardest hitting melee enemies in the game, however has an abyssal hit-rate. If your evasion is good enough, the only thing you will need to worry about is his fire breath and dot it causes. If your lacking in evasion, his weakness to blindness might even the odds.
#048 Belle-(Blue dressed cat girl, Lord of the City)-This boss is both weird and very dangerous due to its unique AI. First thing she will do is summon Bete to distract you. He is effectively a buffed loup-garou and carries nothing but extra numbers to the table. Belle from a distance will drop every debuff in the book on you. Having a wand of nonojan-horse to reverse the status ailments is godsend with this fight. After your fully debuffed, she will either spam fascinate-gaze on you from a distance, or, if you move into melee range, use life drain and intoxicate effects on you. The gaze isn't too threatening right away, however the damage build up on your arousal meter will quickly cause passion's beat, and eventually animal passions, which is an instant KO. Sadly she is immune to silence meaning, the most effective way of dealing with her is either off angle attacks (Shot-shells, redemption, holy water). Or hitting her very hard, very fast with whatever you got (Ie. Scrolls of punishment, Maiden's Snow).
If things go sour, elixirs and lance of fire can cure most status effects (The latter doesn't waste a turn). So pop those if you get into a pinch. Her HP isn't too high, so she won't need too many hits thankfully.
