I would check out rvtrader to get an idea of prices for that model. A drive to Maryland will get you a 2017 for that price.
As for what to look for start with the roof. Take a ladder along and get a good look at the caulking up top. It will probably have some cracking but check along the front and back edges for areas pulled back from the edge. If you see anything suspicious check the walls inside and out for softness. Other than that check the tires for uneven wear. It could be a sign of bad axle alignment or a bent axle. Look at the rims for damage from hitting curbs.
Maybe take a white cup along. Drain some water out of the tank drain into that cup. If it's not clean you probably don't want to be using it to brush your teeth..
