There are a couple of ways to go when it comes to backup cameras, I have tried both.
First: hard wired unit that has a cable from the rear of the coach to somewhere near the hitch area. then a cable from the dash area of the truck to somewhere near the tailgate. You have to connect this every time you hookup the truck to the camper.
Second: A wireless unit that mounts a camera and antenna on the rear of the coach and a monitor on the dash. This works but not well when driving down the road. There is an option that makes this one a little better, that is a cable that runs from the camera on the rear of the coach to the antenna mounted somewhere in the front on the coach, (this shortens the signal path).
Now opinion time, I now have the wireless camera with the cable run from the rear to the propane compartment. I would not do this again, go for the hard wired it never failed the entire time I had the coach. wish I had taken it with me and installed it on our new camper.
dave