Here is a thought. If your coax from outside to the back of the antenna switch has enough slack, put a 2 coax wall plate next to the antenna switch and move the coax to the top (or bottom) connector on the 2 coax wall plate.
Run a short coax from the bottom (or top) connector back to the antenna switch plate.
Put a short coax jumper from the top coax connector to the bottom coax connector.
With that short coax jumper in place, you have the same setup you have now. Take that short jumper off and you have a home run coax from the power inserter/receiver to the coax outside the RV.
Just check to be sure that you DO have a home run from that coax connector to the outside connector.