I just installed a Pioneer touch screen in my MH. It has apple CarPlay as well as android. It has a backup camera input and a video input. So you can have the backup camera work as a backup camera and then switch it over to the video to see behind the trailer. Cameras can be had for around $20. The $20 camera on my Excursion was 5 years old when I sold it and still working perfectly.
I got the radio from Amazon for around $270 I belivee. It will take some labor to install it and some extra camera cord for the trailer but it will work like you want it too.
