I installed a backup camera for our Garmin GPS. No way was I going to drill through the fiberglass wall so I welded up a bracket that mounts on top of the bumper instead. I tie-wrapped the wire to the bumper over to the right then went under the trailer for the power wire up to the A-frame. Spare tire is mounted under the TT so nothing in the way of the camera.
I mounted the transmitter up front in the cabinet above the head of the bed for the shortest distance to the truck. I ran the wiring for the transmitter up through the coroplast, up through a cavity for the pantry wall into the ceiling space, then in the ceiling cavity all the way to the front, all 100% concealed. I used lights, AC grilles & bezels for access into the ceiling and used a fish tape. I had to buy an extension cable for the transmitter. The connector at the camera end has to be outside and it's not a weatherproof connector so used some heat shrink tubing on it.
A lot of work and what bothers me after all that is the grainy image on the GPS, pffft... But it still helps with backing up. The camera being lower down on the bumper works just fine. Cars after all have them low down on the rear too. My DW and I have hand signals down to a fine art and that works better than a camera any ol' day. It's not often she isn't with me.