Not sure where the rear radio is on the newer units: Another "feature" not included in the 2014's--along with the nifty USB charge ports next to the closet.
Never fear, though, I installed USB charge ports all over our Axis. Two in the slide and one in the bedroom near the 120V outlet above the beds. I was able to snake power over from the driver's side reading light (a 2A 5V USB charger really doesn't draw much 12V current--about 1A so it doesn't impact the circuit that much at all).
I did detail the installation of the two over the slide here: http://www.thorforums.com/forums/f27...orts-3116.html
The rear installation was essentially the same procedure, just with the reading light instead of the overhead light.