Basically, EVERYTHING in front of the drivers & passenger seat backs works from a CHASSIS battery which is under the vehicle hood.
EVERYTHING behind the drivers and passenger seat backs works off of a HOUSE battery which us usually found under the step in the entry way. There is probably a big rubber latch on the front of one of the steps.
The round power switch by the door switches on and off the HOUSE battery and those things on the indicator panel. That switch has nothing to do with the VEHICLE systems.
Your in-dash radio and camera system will be powered by the VEHICLE power system.
I cannot tell you what the problem is, but if the radio doesn't light up you probably have a total radio power failure (nothing works) it is most probably a fuse, either in the CHASSIS fuse box or in-line in the dash behind the radio. It also may be a bad ground between the vehicle chassis and the radio itself.
You will probably have to take it to an RV dealer or RV repair place.
If the radio DOES light up, the problem is probably a menu setting. On my Coachmen Freelander, except in Reverse, I have to press a button to activate the rear camera.
I hope I have helped. Sorry I couldn't have helped more.
Tim