Funny I read this all first time now.
My 44 years old Prevost is delamination-free and roof is not leaking. Well insulated as for those off-season camping nights all it took was single electric heater to keep it cozy.
I just found a buyer for it for $20k and will deliver to Oregon next week.
Just check everything couple days ago and beside new batteries and tires that start showing some age -everything is in good working order.
I predict the shell is good for another 200 years, the engine might need some new seals in about 20.
Now my 12 years old, top-end truck camper is all rotten up and I partially rebuild it last year. ... but it has slide.
Good luck on your search.