I would list it in the IRV2 Classifieds, Craigslist, and RVTrader.com. Just be prepared for the scammers, especially on Craigslist!
RVTrader.com offers a "list it till it sells" price with a LOT of pics. Unless you're needing to get rid of it fast at a "fire sale" price, I would choose that option.
I would specify in the ads that you can ONLY accept a direct transfer of funds between their bank and yours, and stick to that unless it's someone local that you know!
Good luck, happy trails, and God bless!