I've been leveling our class C for years using blocks and the Level-Mate Pro. I use a combination of the
double-wide blocks for the rear tires and
singles for the front tires.
IMO, the key to making it easy is the
Level-Mate Pro. This gives me real-time, accurate feedback, showing exactly how much blocking is needed under each wheel to get your rig perfectly level. It allows me to move around the site a bit until I find the most level spot, and then tells me just how many blocks I need under each wheel (in inches; I typically use one level of blocks per inch of rise needed). This improved speed and ease of leveling by orders of magnitude, and now I wouldn't be without it.
Have a spotter when you pull onto the block stacks to make sure you don't overshoot. I build up ramps with the blocks, being careful to have the top of each ramp an equal distance from the wheel. If all goes well, and it usually does, we are up on the blocks an within 1" of perfectly level on the first try!
It feels a bit sketchy the first couple of times you do it, but it's actually really easy and stable and those blocks are surprisingly sturdy. Do plan on replacing a couple each season - the bottom ones can get a bit deformed on really unlevel or rocky surfaces.
We've become so fast and good at this that we sometimes have onlookers complimenting us and asking how we do it so easily. I've definitely found LevelMate some new customers. Just this past weekend I was able to get perfectly level with one side 6" low, in the pouring rain, first try! Took longer to stack the blocks than any other step in the process.
Feel free to message me if you have any questions.