Curious how it's going for you Paulitee. I'm kind of doing the same thing floorwise. I have a 74 Sovereign
that I'm converting to a food trailer. I have three sections of floor that are blown but the rest are sound and solid. I've started the floor demo in the rear but haven't started putting anything back in yet. Essentially I'll be removing all of the plumbing as well as it won't hold up to food code anyway. If I was restoring this for a RV use I think I'd probably do a Full Monty and lift the shell but my interior will be a commercial kitchen so other than the looks it won't really be a RV anymore. Good luck.
p.s. What kind of plywood are you planning on using?