is a continuous thread started years ago with a couple of thousand entries.  Reading through it. And based on a bit of personal experience:  Get a wired two camera system, and a switch so you can toggle back and forth.  they typically wire into the reverse light circuit, but I would connect it to a toggle instead, so you can put it in the rear mode and leave it there.  
I’d mount the monitor jut below the roof of your cab.  In the front center, pretty much where the rear view mirror would be in a car or truck.