I've sold three different RV's via Craigslist. All sold within a few days and I got excellent prices for them. I would not have gotten as much if I had consigned these same units. Your mileage may vary.
You will be much more successful when you advertise your RV if you provide many quality pictures in the ad, plus a comprehensive description, including specs of, and options on the RV for sale.
Dealers generally are very good about providing lots of quality pictures, but not so good at listing original options and full factory specifications. And the lengths dealers state for RV's, I have found are seldom accurate.
Private party ads, I have observed at least in my area, usually provide very few quality pictures, and usually don't provide anything close to a comprehensive factual description of features and options plus specs. Running ads like this will really limit your response from the public.
Good luck!