I've had ours rewired to the RV batteries and a switch installed so that we can turn it on and off. When I start the engine the switch is bypassed and the radio comes on automatically. When we park we flip the switch and the radio comes on. I didn't want to use the engine battery as that could drain it rather quickly......
At that point I had the TV also wired into the AUX input of the radio. Provides much better sound than the TV itself.
I feel this is the setup that should have been provided from the beginning from Forest River. Competitors usually put in a second radio for the living quarters and with the setup/modification we've done I'm more than happy with the radio configuration (don't care must for outside speakers anyway).