12-ton hydraulic jack with the double-extending piston. Allows jack to be short and get under the axle when the tire's flat, yet extend enough to clear room to change the flat. I carry that plus a short jack stand for extra support, a truck-sized 4-way wrench AND one for the nuts on the wheel simulators. 
I'd hope for professional help. Or somebody to help me. Finally, change it myself and I've done it before. I'd just hate to have a service truck roll up and find he'd lost the right socket, had too tall a jack, etc.
A whole Class C doesn't weigh near 12 tons. But, much less than a 12 jack is too hard to pump in the awkward location on the axle to change a rear tire.

This guy. About $20 more than a single-acting 12-ton and very much worth it.