Personally, I found the rear view camera to be not so useful due to the extreme wide angle and I was always misjudging distances when I used it. I have good side mirrors on my truck so I rely on those as well as my wife spotting and talking to me using walkie talkie. But the right side mirror is not too good at seeing everything on my blind side of the fiver.
So I added a side view camera on the right side of the fiver, and I used the same harness and view monitor that I used for the rear view camera, so the side camera is powered by the same harness that powers my monitor....... only on when I'm pulling it down the road, because I disconnect the monitor when I get to my site.
I like this setup. It allows me to see everything that is on my blind side, and it makes it easier to change into the right lane in traffic without running somebody off the road. Recently, it kept me from backing the fiver into a ditch when I backed into a site on the right side of the campground road.