I use tri-levelers. They work well as you can stagger them, i.e., one wheel on first level, another wheel on the third level. Digging up rocks (if there are any) or digging holes is a lot more work than placing the levelers. I carry two small torpedo levels, one for the floorboard behind the doghouse and another for the kitchen countertop. The one on the floorboard helps me position the van while the one on the counter reassures me that the shower water will run down the drain and not to the front of the van soaking my rugs. After using the levelers for a while, you get a feel for which wheel needs how much elevation change for level. When I run into that situation where they aren't tall enough, I carry a 3 ton hydraulic jack to raise the low portion. It also helps with a tire change if needed.