Let's face it. You are going to have problems. But, it is usually less expensive to deal with the problems than to buy a van with no problems. Basically, any used unit will need some kind of fixing. You can get it fixed just about anywhere and there is all kinds of help for the RV side on YiuTube and places like that.
If the bones are good, change the oil, do a flush and filter on the transmission. Also, get the cooling system flushed and get new belts ans hoses while you are at it. In other words, do not skimp if you think it is a keeper. Also, get new tires and an alignment. Get an "E" load rating, which some tire guys call a 10-ply.
RVs always have something wrong just like a house. Make sure the chassis mechanics are in good order and stay that way. Then, you can always get somewhere to fix the rest.
Finally, check with an RV place for the sealant to use on leaks. There are several kinds. While Camping World is great, you sometimes get better advice at smaller places. Good luck!
