Frequent washing is the key to having an RV look good a decade later .
I am a car guy and I detail my cars frequently using a clay bar and expensive brand polishes and other chemicals on my cars ..
I use palmolive diswash liquid and a truck brush ( 9 inch wide x 3.5" deep on a 6 foot handle ) to wash my TT .
Without exception I wash my entire TT after every usage .
I lay down a stripe of palmolive on the brush face and then do a 10 sq. foot section .
I use a 5 gallon pail of HOT water to rinsh the brush each time .
And of course a garden hose .
There is an advantage to laying down a stripe on the brush versus just using a pail of soapy water .
I do the roof and the awning the same way .
For the tight spots I use a good wash mitt .
I squirt a little palmolive into the mitt and go to work .
I did plumb a One Inch spigot and I use an oversize 3 /4 inch garden hose with a high volume nozzle to make rinsing faster .
I don't wipe off the siding but I do use clean old cotton bath towels to dry the windows . Probably not mandatory .
I have found through my experience that frequent car washing ( or waxing ) is more important than the products that I use .
Our car club has auto products reps ( MeGuiars ) put on a clinic every 2 years .
They say the same .
I have tried all of the high class brands and I use MeGuiars products now and I find that theirs is as good as the best .
They make a good Car Wash Soap that I buy at Costco in the gallon container .
There is no substitute for elbow grease .