Your particulars may vary completely from ours but we were very happy with the dealer trade-in. We had a 2006 LTV Sprinter van with about 70,000 on it. Loved it, needed a bigger RV.
Made a half-hearted effort to sell it ourselves but only one test drive, no firm offer at the "going asking rate" which I had determined by looking around online, maybe too high...
The dealer gave us almost our desired selling price on the van in trade when we bought a low mileage used 2013 RV in February. He sells new LTVs, so that may have been a factor.
It was great to skip over all the hassles of showing the RV, paperwork, money transfer, tags, and so on.