Plug the entrances with anti rodent expanding foam.
We had an infestation in our 2008 Puma. First find the entrance. Mice can squeeze thru a hole the size of a nickel. Have a partner shine a light from storage at all plumbing outfall areas, under the sink, electrical outs, anything going into the mid level area of RV. Seal wherever you see light with antipest expanding foam. Then do the same thing underneath your RV. Seal all the holes. They can't get in. Then wipe down the interior of your RV with a bleach soap solution top to bottom, stem to stern. All of the other suggestions are also great. Good LucK!