First of all, kudos for working over this mod.
Due to the great size of the project, it's understandable that the game is highly unstable, so I'd like to help by sharing the "minidumps".
I hope it helps on fixing those issues.
The game often crashes when trying to go to Bullworth. For this reason, it's really hard to reach that island: I've tried 3 times. Two of those times, it crashed.
I tried both: flying from Liberty City to Bullworth and flying from Mainland Liberty to Bullworth. Same result.
The third time, i tried again from Liberty City, and this time, it didn't crash. Seems like random.
Here there are the minidumps, let me know if more are needed, that place crashes very very easily for whatever reason.
Bullworth Vending Machine Crash
During the third time, i managed to reach Bullworth. I went to the academy, I entered the boys dorm, everything was fine. Entered the Girls dorm, found a vending machine, tried to use it, and then BAM, game crashed