I just gave the motorhome a bath today and used my new foam lance(also known as foam cannon or foam gun). A foam lance is a pressure washer attatchment that you fill the bottle with soap and water and it turns it into thick foam that it sprays at low pressure. They sell special soap but I have found it works pretty well with any normal car wash soap, laundry detergent, or dish detergent. It makes it a bit easier because you can spray soap foam on the motorhome and start washing with a long handled washing mop and not have to keep dipping in a bucket to keep soaped up.
I didn't buy it to use on the RV but it sure is a help. I got mine for about 65 bucks on amazon but you can get them other places on the web.
There are some videos of them in action on youtube for those that are interested.
