We bought our TT off Craigslist back in Feburary. Very smooth transaction. Paid in cash and went to DMV to transfer title. No problem. Selling a outboard right now thru craigslist also. Guy put a cash deposit on it for us to hold. Bought 2 other outboards off there in the past 5 years. Also bought a 17ft tri-hull boat a few years back. Plus my weight distribution hitch. All transactions done in cash. Only problem was the first outboard we bought the seller wasn't honest. Did not tell us the prop shaft was bent. But he was also a 16-19 yr old kid.
As a side note..... If you are a member of Facebook... there are yard sale group pages for your area. I have seen campers listed on these sites also. Granted, they are few and far between. But I have bought smaller items for the camper on these sites. Basically just agree to meet in a public place and exchange cash and item.