I am a new MH owner, and have never camped in anything before (I purchased an older used Class C to go to dog events). My unit is pretty basic, and I learned to level it very easily. I practiced in my driveway a few times, and now I'm a pro. :-)
The thing to remember is that you are leveling the REFRIGERATOR! I bought a cheap torpedo level at the hardware store, and used it on the floor of the freezer compartment (interestingly, the freezer floor and the fridge floor are NOT the same, but I went with the freezer because it is metal and right next to the fins). You have to check the level both side-to-side AND front-to-back.
I spent quite a bit of time and effort (at least for me--about 30-45 minutes) getting the level perfect, and then I attached two small graduated levels in the cab area. One to the driver's door for front-to-back, and one low on the dash above the parking brake for side-to-side. Now, as another poster said, I can use those levels when I park to find the best spot. I am carrying a couple of 2 x 8's, 24 inches long as well as a set of the plastic lego-type leveling blocks. I generally am not camping in campgrounds, so I probably have to deal with more uneven ground than most, hence the pieces of wood.
At first I lusted after automatic levelers, but after the reading I've done here, because of the extra weight, I wouldn't want them on my smaller class C. Plus, the leveling thing is not that difficult in the manual mode.
I've only owned my rig for a couple of months, so I'm feeling good that I can actually give advice to someone else on here--I've received a lot of great help on this forum!