Sometimes lug nuts are put on at the tire shop or truck with out regard to proper procedure.
They simply use a big air gun and hammer the nuts home.
A better grade technician will use a torque wrench for the final setting.
If your coach has been abused by the techs that don't care, there may be a problem getting the lug nuts loose.
The X 12 is used by many folks with coaches that torque to 350-400 lbs and need removal a few years later.
X 12 Plus Geared Lug Nut Wheel Wrench | eBay
Overkill for 150 lb lug nuts but it does work.