A four-ton hydraulic bottle jack will lift one corner of a Class C. The problem is that we're in an awkward position under there and it's very hard to pump the handle hard enough.
I have a 12-ton, old American-Made Blackhawk that I just love. Very easy to lift the coach from "down under." But it's heavy and awkward to position.
My MVP package turned out to be a 10-ton Harbor Fright bottle jack and an old but very rugged 4-ton small steel jack stand. I had a brake problem out of town and found I could just fit the 10-ton and the jack stand in the space between shock absorber mount, spring, and tire on he passenger side. Passenger side's tighter than driver side, at least for me because the track bar mounts there.
I just looked the HF site and it seems they have only 8- and 12-ton right now. 10's no longer in the product line. They offer 12-ton in a low-profile version and that would intrigue me. Remember, coach is a few inches lower on a flat than an inflated tire. Kinda Captain Obvious remark, but keep it in mind.
You also need something to stabilize jack and stand on soft ground. I've found where anything "two-by" was too thick. Thinking 3/4" plywood a foot and something square or even 12" * 18" might be the best single pad. I think it's good to have both jack and jack stand on the same support piece.