In your price range it sounds like a good deal, quality built lasts. something newer not built as well is not the answer. Your budget in not in any new class A range. There are licenced RV inspectors (NRVIA) just like home inspectors, they charge $250-$500 around here. Search NRVIA in your area.
https://nrvia.org/ I guarantee they will find something wrong, but new similar equipped coach is going to run you $150,000 plus.
As far as service I change my own oil once a year and it runs under $80.
Warning if you get a DP with air ride it will be hard to ever go back the truck leaf spring suspension.