1. gut interior 2. brace body 3. cut 4. fab new floor 5. remove braces 6. reinstall interior If your starting with a rusted hulk like me, you can skip steps 1 and 3
I never touched my floor. just dropped the body and filled the gaps. didn't have to build any new body mounts. I did it that way because I'm not smart enough to follow instructions given by others. I would suggest you do all the research then do it your way.
Don't take this the wrong way, but are you aware of the "search" feature? There's a lot here on channeling that you'll find helpful. Take a while to go over all of it & if you have any specific questions after that, fire away.