FB Marketplace, RVtrader, Craigslist are all good places to shop. I wouldn't rule out dealerships. Often they have a centralized supply of inventory so they are a great place to shop, have financing options, and usually negotiate more than private sellers who are emotionally attached to their RVs. You can guess at condition but you won't really know things like leaks, mechanical issues, electrical etc, unless you really know what to look for or get a private party to do an objective inspection. It can cost a bit but well worth it in the long run.