LateNightMC

I've been having multiple issues attempting to install/reinstall forge along with a few other mods just to try out a different MC experience. Initially I started with a new 1.4.2 .jar, installed forge first, then optifine (testing those two first with magic launcher and seeing no issue in text until I loaded a new world and immediately fell through it). Loading it through the regular launcher though it seemed to work fine. I then added Too Many items and then Rei's Minimap, still not experiencing issues. After adding millenaire (the whole reason for installing forge in the first place) I'm unable to play for more than a few moments after loading a new world (up to about 7 minutes) before MC freezes and crashes. I uninstalled and reinstalled numerous configurations and can't figure out what the issue is. I'll be the first to admit I'm not the most tech savvy person but, after exhausting the search bar and wiki I can only find similar instances none relevant enough to solve the issue. Any help at all would be appreciated.