I wanted something like you're describing and the decision was made easier at Xmas when my brother gave me a Garmin Overlander to use for my truck. I didn't purchase the navigation package that was offered but have the large touch screen for the radio. The truck came with a back-up camera which is located in my bumper. Yea, different type of truck but I also wanted a camera to see behind my camper. Garmin has a wireless camera/transmitter that syncs to their unit and with an easy prompt I can see the Jeep and any traffic behind me. Like Kayteg1 described, I mounted it inside the camper wired into an overhead light and hidden by the window valance so it's centered. It works great, freezes still on a rare occasion for a split second and comes back. I can easily remove the camera/transmitter if needed. I know it's not exactly what your needs might be but guessing the year of your truck you probably need some type of dash mounted screen.
