Camera for back of trailer

I have a $100 car license plate mount wireless backup camera. When I mounted it on the motorhome license plate it was useless because of the poor depth perception. When I mounted it 8 feet high inside the top of the back window, aimed down so I can just see part of the spare tire, I find it very useful backing in. Wonderful in a parking lot where I can easily and safely back up to within a foot of a pole or whatever is there. It isn't very useful on the highway because of being aimed downward - though when pulling a utility trailer I can see most of it and be sure the kayaks are still there.

I would replace it immediately if anything happened to it. Tempted to get another to look back at roof level to watch for trees when backing up. A side view would be very nice, too, as I have a blind spot when approaching a road at an angle.