Hello, looking around at a search for RTT I couldn't find a lot of info on trailer mounted units. My specific questions are, is a trailer mounted unit the same model as a vehicle mounted unit with a shorter ladder? Can I purchase a regular unit or does it need to say spefically "trailer mount"? I have 3 round tube yaxima crossbars on my trailer that it will need to mount to. Any suggestions on which one to get, approx. price, and how many people will it sleep? Thanks in advance! Jason