Yeah wow this sounds like a huge project.

I also want to compare the database or something. I feel like the best way is to install the newest version somewhere, fill the database with old db information, install appropriate hacks, see if any custom database fields are required, compare all files and redo any necessary change.
Yikes and when I'm done weeks later

that's when the real fun begins when you get to pinpoint the bugs and errors. haha oh well, guess it can't be too easy.