It took Thor until model year 2017.5 in the Hurricane to connect the outside TV to the bedroom radio, which powers the outside speakers.
If you go the Bluetooth route, try pairing your phone or similar to the rear stereo first and see if it will reach your phone near the outside TV. I dont know if the BT adapter and phones have the same range, but it is a simple trial. Another option would be an FM transmitter, but that would also have a limited range.
__________________
|