Kind of cheating here... I use Rain-X "Wash & Wax" with Carnauba wax beads on all vehicles and the trailer. I found an adjustable 12 foot screw-in paint-roller handle that screws into an EXTREMELY soft nylon scrub brush with long 'bristles' that are about as soft as a baby's bottom. Found these at Home Depot. Trailer looks good and I have found that the bugs &etc wash right off in a snap, and the job (except for the roof) gets done in about 2 hours. This works best on a cloudy day!
Rain-X glass cleaner is also the best thing I have found for getting rid of bugs on the windshield!
Jim & Kathy
2012 Crusader 290RLT TE, TrailAir flex pin: 2012 Toyota Tundra 5.7 SR5 Dbl cab 4X2 Tow, 4.30 gears, RideRite air, TRD cold-air induction & dual exhaust: Reese 16K Slider: TST tpms
Miles towed to date: 18,950 Nights camped 192