The cable that was originally in my water bay is no longer there. I haven't pulled the panel to see if it is laying behind. For those who may read this, if the cable passes through the selector box above the driver, it may not work for modern satellite TV. I'm no expert on this, but from what I've read, it will not work to run satellite TV through an old box like that.
I took the panel off at the windshield pillar and there are a lot of electrical wires running through there down to the electrical bay. But, the factory sealed the area around the wiring to the extent that I was afraid to interfere with it and risk damaging some wiring. I did find a solution though. I started at the electrical bay. There's a rubber boot around the wiring going up into the coach and into the pedestal at the left of the driver's knee. It was easy to push the coax up into that pedestal. From there I ran the coax to the rear of the pedestal and then there was room and flexibility enough to run the wire between the edge of the box and the wall and then up behind the front curtain shroud. I used cable clamps to run the wire up to the top of the shroud and then to the inside of the curtain track. From there it goes to a ventilation louver on the left side of the TV box and then through the cabinetry to my TV equipment. When we set up camp, we can just run the coax that is rolled up in the electrical bay down through the existing port to the satellite antenna. Originally I intended to permanently mount the dish antenna to the roof. Prior to doing that, we were in a spot where had it been on the roof, we would have had no reception due to the trees. There's some advantage to using a portable antenna.