Jason at Thor customer service was awesome. He understood exactly what I was trying to do and walked me though. I pulled the panel in the upper cabinet that had the power outlet and power antenna switch. From there I could see the three coax wires that go into the antenna switch. One clearly comes down from the roof, one goes to a three way splitter, and one comes from the rear of the coach. That was the one from the outside where you would hook up the cable coax. I removed that coax from the antenna switch and put it through a hole I drilled in the panel. Total time, maybe 15 minuets. And the roof antenna still works to all three tv's as I'm using the hdmi output on the sat receiver to the extra port on the hdmi splitter. And I'm getting sat to all three tv's as well.
The bad news is we spent 1hr and 45 mins on the phone with Dish, went through six people and had to call back once. We never did get service activated!!!
The down side is I lost cable TV in, but only used it once at a KOA. And I can always put it back in a second if needed.
Thanks to all that replied!
P.S. While waiting for Dish, I realized how much I love my Thor. We have our little issues once in a while, but nothing that killed a trip like our last 5th wheel.