I wash my trailers at home by hand. I've found a really soft brush that I use on the roof and a microfiber mitt on the sides. I can wash my 25' in a little over 1.5 hours and about 2 hours for my 34'.
I use an automotive paste wax once a year. I've used Meguiars and Turttle wax the last few years with good results. I have also used liquid Walbernize that Airstream reccommends, but I prefer the paste. Waxing takes a half day at least.
2014 Silverado 1500 Crew Cab 5.3L maximum trailering package (yes, I'm towing the 34')