Buying a used Class A Repairs to Expect?

I'd definately check batteries. If you don't have good batteries it could affect the controls of other things and make you think they don't work, when in fact it's low batteries causing the problem. Like furnace, A/C, refrigerator operations. We purchased a 10 yr old class a 7 years ago and so far just tires and things like circuit boards. Vent and skylight covers can get brittle and crack. We have replaced those. When checking the roof, just go ahead and use etrnabond on all seams and around vents etc to ward off future possible leaks.