UOnly you know if the floor plan works well, and only you know your budget and ability and time to fix things. Personally, I'd have kept the old class c a lot longer except it needed rings which means a rebuild, and I didn't have the money for that. You should be asking a mechanic for a compression check, which will also show you if you have ring issues, like I did. I was shocked and if I had known more about looking into engine problems, I'd have never bought it, but it was too late.
Hot water heaters and fridges are normal wear items. So is the roof top ac unit. You have to plan on or budget for all that within say 3 years. Same with redoing the drum brakes, wheel bearings, all fluid changes, front windshield replacement and ALL RUBBER components underneath the hood and in the suspension. It's a lot of work to redo an older gasser but if you like the size, the floor plan and the overall "look", then it's ok.
Newer units from about 1997 (Ford V10, GM Vortec) on have more powerful motors, 4 speed OD trannies, are wide body (102" vs 96") and are getting away from the ribbed siding look to the flat panel look. Be advised that you have to check for delamination on the older flat paneled units. That is almost impossible to repair for any decent price.
How's the roof of your rig? Is it EPDM (rubber), tin or what? Each type had its own issues. I knew nothing about roofs other than it needed re-coating, and I used 2 gallons of some white roll-on roof coating. It worked ok. Stay away from using clear silicone caulking, it isn't waterproof and is a royal pain to remove.
Then you should consider updating the battery inverter/converter as the old ones do a poor job of charging your house battery correctly. (I never knew that) Refer to the electrical section of the forum and look up SternWake's many many posts regarding proper battery charging.
Again, if the drivetrain is sound and you don't have any more areas of rot (inspect below your windows carefully and also by your water tanks at the flooring) then I'd probably keep it, as long as you like what I said before.
Don't despair, it doesn't have to be all done in a summer. Just get the rot done first then it's item by item. By the way, it never ends...
Dusty