When we bought our truck to tow a 5th wheel I put in a backup camera for the truck because it didn't have one. The mirror/monitor I put in had a second input to hook in another camera. My DW suggested putting a camera in so I could see inside the bed of the truck to more easily see hooking up the trailer. So bought a cheap camera. Attached to 3rd brake light and then plugged into the mirror/monitor. Then put a stripe of white duct tape down the pinbox. When backing up you just aim the white stripe for the opening in the hitch and before you know it, you are hooked up. Worked great on our last 5th Wheel and is working great on our new Jayco. I am sure you may have seen this before but this was the DIY that I did for our setup.
DL