Yes, you are likely to see a BIG loss (less so if you find a private buyer) unless
you can find a dealer that knows he can easily sell your RV with you buying an RV he wants to move out. Then, you might break even. Many Sprinter based Class-C RVs are sweet.
Have you checked out RVTrader.com: RV Sales - Class A, B, C Motorhomes, Travel Trailers, & Pop Up Camper RVs For Sale
? It's a great free resource for RV shoppers and sellers. Free to register. You should be able to get a good idea as to the worth of your RV.
I'll be attending my first FMCA event in Springfield, MA early next month. It's not unusual for RVs to be bought and sold at RV rallies.
The Escapees annual bash, "Escapade" starts in a week in Essex Junction, VT. It's not unusual to have attendance top 1000 people at Escapade.
If it's just that you're not confident in driving your RV, a quick Google search with turn up RV Driver Trainers. They can come to you; you can go to them or, bigger RV rallies often have driver training programs available for a fee.