I'm thinking, now that it's almost 2019, to do a big upgrade to the sound system/navigation/ back up camera, and have the whole thing controlled by a small tablet that can be mounted to the dash and taken off when parked.
For the stereo, I'm trying to find a blue tooth driven amp that can feed the (4) 6x9 speakers in the back, as well as the speakers in the cab.
For the back up cam. I found there is a number of blue tooth controlled camera's that are simple license plate covers that can snap in, and a tablet with cell data plans should be able to use nav/music apps. (we also need to use the nav apps for our speedo as i think our speed control servo is out)
If folks have some ideas that's great, otherwise I'll post when I find a solution.
Lars