William,
I have a 2007 TourMaster and also have been dealing with closing all the possible routes for mice to enter the coach. For wiring pass though the factory used an expanding foam in a black color. I used some window sealing expanding foam from the Home depot to seal those places I found that did not have foam where it was needed.
In the cabinetry inside the coach, I have added metal screening and some coarse stainless steel wool or plastic 'scrubbers' stuffed into small openings, etc. I have used expanded metal mesh to screen the heater registers and dash air vent intake as well. You can see some pictures in my thread in the Class A section titled "fixing little things..." at
viewtopic.php?t=2249
Chuck