I'm sure you already know this but I'm still going to say it, the studs in a trailer are slightly less than a house (not 2 x 4). Be sure to use fasteners that will not protrude your outside walls... I think the stud in a trailer is 1.50 x 1.50, I don't know the exact measurements off the top of my head.
In our trailer I made a backing plate that I fastened to the wall with liquid nail and fasteners, painted it to match the walls, and then attached the TV to the plate. I did this because I went to a larger TV and wanted to make the mounting a bit more firm than just the wall itself. I also moved the mount over a bit centering it on the wall (MY O.C.D. DISORDER KICKED IN).