I am using Griot's de-ionizing tank system to wash my rig. With a 14" truck washing brush head and super lightweight telescoping handle, I can wash the whole thing in about an hour. I use a telescoping water wand with adjustable spray head too. This lets me cascade water from above rather than shoot water up at the bus with a normal hose nozzle. No drying required. I spend another 30 minutes getting the really tough bugs off of the front and use a clay bar on the windshields with Griot's Speed Shine as a lubricant. 1.5 hours if no lolly-gagging and she looks amazing. With the de-ionozed water I can wash in direct sun and get NO spots. It is awesome. Replacement resin for the tank only cost $85. Resin life depends on how much water you use and how hard your water is to start with.
Considering a visit from the mobile wash guy at the race track usually runs $100 and leaves me full of spots, my home system is awesome.