Maybe something like this would be best. Self contained, rechargeable, no wires to run, wireless. Magnetic mount maybe even pointing out one of your windows would enable you to see the traffic coming behind you.
Hopefully you get where you're going in the 4 hour run time.
Or at the very least, it helps you know exactly where you do want to mount a permanent camera.....
https://www.pplmotorhomes.com/parts/...mera-swift.htm