Security system instead of RV specific system?

Actually not a bad idea. If you had an overhead TV, you could use two side cameras, rear camera and forward facing roof camera. You would have quite a view of your surroundings while driving. It's illegal to use the overhead TV while driving for watching a show, but as a camera system, it might be legal.

You could even put a camera under the front bumper facing backwards and see what your tires are doing. Lots of options with all those cameras.