I installed an aftermarket radio/GPS in the truck that includes circuits for 2 cameras (front and back). The normal backup camera is on the license plate. I ran the second cable to the back and installed a small camera in the back window of the TC. It is not hi-def, but I can see behind me anytime while driving or backing when the license plate is blocked.
I can also access the camera inside the TC with a portable dvd player to use as a security camera.