Wow. You've got a huge job ahead of you. Bad roof, bad floors and from the looks of the pictures the wall is collapsing on the driver's side. Might I suggest a can of gas and a match?
I'm guessing you'll need to start disassembling from the top down until you have a bare chassis. IMHO, not worth it. However, if you do a complete rebuild you will have a coach just as you want it and probably better then new. Depends on your skill level, bank account and patience.
1995 Coachmen Santara 360MB 36' w/slide.
Ford F53/460 chassis, 1997 Jeep Grand Cherokee "toad"