ModLoader v1.0 for Monster Girl Dreams v15.1
As promised, here's the mod loader I've been working on, along with a mod that adds a high-level succubus, Fiore, to the Mountain.
ModLoader doesn't tamper with Monster Girl Dreams, and is designed to have as light a footprint as possible - it doesn't interfere with any other mods that you install by hand - but due to the bug I outlined above, the zip does contain a replacement LoadDatabase.rpy file.
To install ModLoader, just extract it into the Monster Girl Dreams directory.
To install mods, extract them into the "ModLoader/mods" folder and run ModLoader.
N.B.: After installing mods, you must update your save in Monster Girl Dreams. This can be done from the Options screen when you are at town.
EDIT: The ModLoader folder now contains ModLoader.py and ModLoader.exe. Both have the same functionality, but the EXE doesn't need Python to be installed.