I use a 12 ton hydraulic bottle jack. Mostly because I already had it. If I were to buy a new one, I'd buy a 6 ton model, just because it's a little lighter.
You may need to buy a low profile jack. Measure the distance from the frame to the ground on the camper and subtract the height of the tire sidewall and buy a jack a little less than that height. That'll ensure that it'll fit under the frame when the tire is flat.
I also take a pair of 2 ton aluminum jack stands with me. They are lighter and smaller than any cribbing or blocking that I could carry.
Salem 29RKSS Pushing a GMC Sierra 2500HD!
Gotta go campin!