While I probably should find some wood to knock on, I haven't had a rodent in either trailer (since 2011). The only bugs have been those that rode in on me, and some no-see-ems that managed to get through the screens in Florida. I did have detachable power cords on both trailers. I also remove anything edible (including soap, etc) before storing the trailer. Paper products, the mattress, etc stays in the trailer. I do remove all clothing, sheets & blankets, etc.
My suggestion would be to check underneath for any openings that Escape didn't fully foam closed, if you have the permanent power cord and leave the trailer connected, be sure to stuff around the cord with steel wool or the equivalent, and, just to be sure, put an electronic mouse trap inside. If you remove the anode from the water heater (and I suggest you do to clean it out & be sure it is drained) either put it back, a new one if necessary, or a plug.