Dannys truck wash in Phoenix, off of I-10w across from the Flying J will do the undercarriage, and do a very good job! you can also get the whole rig waxed, and the wheels polished if you want! Also Little Sisters Truck Wash will hand wash and also do a very good job, they also have wheel polishing! locations, Eloy, Az., Barstow, Ca., Victorville,Ca. Truck Tub west of Kingman, Az. on I-40, you have to go past it going W. get off at the next exit, turn left, left on the frontage rd. All of these washes do hand wash, power spray rinse. If you want them to just hose it off, they can do that also!
There is one wash I will tell you to avoid, That is in Las Vegas across from the TA Truck Stop. They have very high pressure, and have damaged many paint jobs, and filled one of my friends Mack truck with water
! He opened the door to leave, and water poured out
! Not just a little either!
If you ask them to be gentle with you MH, and back off with the high pressure sprayers, or just hose it off, most will do that for you!
There are many others across the country, and they will all wash MH's, but expect to wait, if there is a big line, because it takes awhile to wash the big rigs! Rail!