Fresh Cab seems to be the most recommended solution:
Amazon.com: Earth Kind FC6 Fresh Cab Mouse Pouch, 4-Pk.: Industrial & Scientific
Look for sources of food and get them away from the camper - like tree nuts and bird food.
I like the Victor sonic pest chaser but the thing to remember is that it will not go through walls so it would need one per room. I have one under the sink on an extension of the winter.
Last year we have a black snake move into the trailer - That seemed to keep the mouse population at 0, but DWs first words were "let's trade it in!". (never saw the snake, just the skin.. ewwwwewewew!)
2011 PrimeTime Tracer 2600rls
2001 GMC Yukon XL 2500, 6.0L 4.10:1 axle ratio
Nights camping 2014 - 17
2013 - 15