You have to be very careful on which chemicals you use on your roof. Depending on your roof type, there are different kind of cleaners recommended. I found this article to be helpful -- http://www.mydrv.net/roof_maintenance.htm
As far as cleaning the sides, I am always careful not to use a product that will strip the wax. I know they are often gimmicky, but I generally stick to the name brand products dedicated for an RV - such as wash, awning cleaner, etc. While they often seem to take a little more elbow grease, I at least feel safer.
On the tires, I generally just clean them with water and a brush. I try to keep away from tire dressings and the like as many of them will speed the breakdown of the rubber in the tire.
Hope that helps! Terry