2wd to 4wd swap

[RustyHunk-O-JunkGuy]

Anybody out there that could answer a few questions for me? I'm looking to pick up a 67-72 suburban now that wife and I have a couple kids. My folks had one when I was a kid and you can't beat the trucks when it comes to looks, solid build and just plain awesomeness. Only problem is every truck I've found for sale lately is 2wd or a very beat up/ over priced 4wd. I really would like to get a 4wd (auto so the wife can drive it)!

Somebody has got to have made the swap before. What all is required? I know the front spring hangers are riveted on the 4wd trucks, but that's about it. Front crossmembers the same by chance? What about center crossmembers, do I have to grab the 4wd crossmember for any transfer case mounts? Are the floor pans/ trans tunnels the same? Is there any sort of raised area for the quadrant for the transfer case boot to mount to on the 4wd truck floor that isn't there on the 2wd? Steering boxes and locations the same right? Also is there any chance the driveshafts being the right lengths if I find a long bed truck for parts? What was the common gearing usually in the rear 2wd verses 4wd?

On a related note if I wanted to swap a 700R4 into it while I'm there what years should I look for?

Any help would be much appreciated.