Around here, the lowballers get most of the mobile home parks. A single wide goes for $75 and a double wide $100 at best. I don't advertise for mobile homes for this reason.
What happens is the mobile home owner gets cited by the park that they need to get their home washed. Every spring an inspection is done listing for each tenant what needs to be done. The tenant needs a receipt showing they had the work done. Even if they get a crummy job done, it get's them by until the following spring.
I've seen young guys, maybe seniors in high school running HD washers, blasting mobile homes for 40-50 bucks. They use no chems at all, just high pressure. At that price, they get plenty of customers lined up. The perceived value is now lowered in the eyes of many mobile home owners.
If people call for a quote, I do a verbal over the phone of 100-125 for single wide, and 125-150 for double wide. It doesn't matter if I don't get the job, because I'm not going to work for less.
I hate to say it, but if people could afford a house, they wouldn't be in a mobile home watching their dollars. In other words, there are better places to advertise where you can make money.
Anyway, wash them just like you would any other other house, be it vinyl or aluminum.