Not sure you still need answer Don but will give my advice, hate to see questions unanswered.
Looking at your
coach brochure your amp,DVD, receiver cabinet has a channel off left side, over door entrance, to front "A" channel location to front cabinets over windshield area.
The channel also has your curtain within it also.
The new RCA connector cables can run through the overhead above curtains as I did when I ran wires for new surround DVD system for rear speakers in my kitchen area.
You will need to use a drill large enough to get RCA plugs through hole for a wire and plug getting wires through.
The ceiling will be blocked running wiring front to back but can be fished from sided wall to sidewall.

If you have TV out you may see the exsisting wiring maybe running through channel in ceiling to amp cabinet from TV location.
If you look in
Quick Tips link you will see these pictures and others to maybe give you some ideas.