The MH we bought last fall didn't have a backup camera, but I wanted one in order to watch the toad, among other things. My research indicated that wireless systems were not always reliable so I bought a kit that included the color monitor, wire, and camera off eBay for around $140.00. We built a combination tire hoist/camera mount on the back, ran the wire underneath, and mounted the monitor on the dash. It worked beautifully on our 7k mile trip this Summer.
IMHO, a wireless system would certainly be easier to install and may work, but a wired system is more positive. This may not be much help, but it's the way I looked at it.