The commercial "RV" products may work, but many have found they are not needed. A bucket of car washing soap, a bit of bleach, a soft brush is about all you need unless you park it under some serious trees that drip sap all over it.
When I first bought my previous MH I asked Thor what to do. They said spic N Span in a bucket of water, soft brush, no special conditioners required. Dawn does a good job too. So you can buy a product or squirt some dish washing liquid in a bucket.
2016 Newmar Bay Star Sport 3004