I am another advocate for selling on CraigsList. Clean out the RV. Make sure it is as clean as possible inside and out. Remove as many of your personal items as you can from the rig. Take at least 6 pictures of the inside and outside. Put your best picture first. A shot of the RV at a beautiful scenic site is best. Include a floorplan if you can find one on the web. Write a very descriptive ad that lists everything that a seller would ask about, mileage, price, and any obvious defects. This eliminates the tirekickers and those who can't afford your RV. It also may drive away some buyers who are looking for a cheaper one or one with fewer miles on it, but they aren't your customers anyway. Use paragraphs and a spellchecker to make your ad easier to read.
Be sure to list the good things about your RV as well. Service records help close a deal. Make sure everything works as built or your ad lists exceptions. Research CraigsList to see what your competition is and price yours accordingly. Most of the higher priced ads have likely been up for a long time. After posting, check back often to see what else has popped up. I try to price my vehicle just below what the average is.
I always put a line in my ad telling scammers not to even try but that doesn't always work. Scammers are easy to spot. If it looks at all suspicious it is a scammer and I don't answer. My ads also state no trades, no payments, no sob stories. Be prepared for folks who never mastered reading comprehension. Answer all legit inquiries quickly. I generally try to make the third exchange to be either face to face or over the phone rather than email.
This has worked well for me for many years. I always sell my vehicles quickly and usually to the first person who comes out to look at it. My selling price is usually above what the Private Party book value is.
I am NOT a mechanic although I do play one in my garage!