The first thing most will tell you to check is the age of the tires. Anything over 7 years old need to be replaced, regardless of the tread left. There's been many a story posted here as to the destruction caused by a tire that blows out due to age. As for everything else, make sure you are shown how to operate everything. Furnace, water heater, water fill, dumping the holding tanks, where all the fuses are, how to check fluids, the stove and oven, the microwave, the TV antenna. In short, everything. Don't fail to ask any question because you think it too silly or stupid. And don't hesitate to ask questions once you have it, either here, or of fellow RV people you bump into at the campground. You'll find 99.9% more than willing to help a newbie.
Jay & Peggy Monroe with Dolly
Can't take it with you - don't plan on leaving any behind
2016 Newmar London Aire 4553, Spartan chassis
Wrangler Unlimited toad