The car wash is a dandy idea except for the pressure washer part. Pressure washers and trailers are not BFF....hard on the decals, can force water into places it shouldn't be and other assorted things you don't want. Go ahead and use the soft brush and then turn the water pressure down as low as possible and gently rinse the soap off. You could get down and rinse off the undercarriage if you feel strongly about it. Any concerns about the inside, can be solved with a couple of flea-type foggers. Secure it with some tape to your table or wherever while you're in transit and then open up everything for a couple of hours when you get stopped. You'll need to wipe everything down after the foggers, but they may help.