I bought my rv used. The previous owner installed a 2in rec hitch. It has 3 receivers, the 2" in the middle then one on each side. He use to tow an enclosed cargo trailer with his Harley and some other stuff inside with no problems. You can also install a cargo carry platform because of the 3 receivers. The only trouble I had was that the receiver gouge the asphalt when backing into my storage unit because they have such a high pitch in front of the door. I just had 2 Ultra-Fab 3" departure rollers welded to the bottom of the hitch. Now the receiver doesn't scrape anymore.
I plan on getting a gas golf cart to tow behind my camper. If I do I will be definitely be getting a single wheel swivel wheel trailer that can fold up.
http://www.cruiserlift.com/swivelwheel.html