Your camper should have levels on it, if not, it might be wise to get a couple and place them on the camper after getting it perfectly level.
I usually use chopped 2x6s stacked up to drive up onto to level out. I also carry some plywood squares (3/4" thick) as well for when I need less than the thickness of a 2x6.
Follow me as I full-time the Redneck Way at The Journey of the Redneck Express CBChannel 17Redneck Express '1992Dodge W-250 "Dually" Power Wagon - Club Cab Long Bed 4x4 V8 5.9L gashog w/4.10 Geared axles '1974KIT Kamper 1106 - 11' Slide-in
I tried the stick on levels and did not like them. I take a 6" level with me and place it on the middle of the floor and make my adjustments. This is for dropping the camper which I do pretty much every time. On the truck I have several squares of plywood that I use to drive up on.
2002 Chevy 2500HD LS Extended Cab 4x4 6.0 gas 4.10 rear SWB
2007 Lance 845
MSgt USMC retired
Use 2 stick on bubble levles on left rear corner-use for lowereing raising camper. At camp-simple wood 2X6s-if needed, carry six to poasition truck. Can sight both direction with levels-if not off loading release tiedowns if needed to levle camper with jacks.
Heres what I use. They offer varying degrees of lift. I carry 4 of them since I have a dually. On a SRW truck 2 should be fine. They store well in my slide out tray so they are always handy to get at. Never had any cracks or breakage.
2009 Chevy Silverado 3500 dually D/A, Supersprings, Stable Loads, Bilstein Shocks, Hellwig Sway Bar, Front Timbrens.
2010 Arctic Fox 1140 DB, 220 watts solar, custom 4 in 1 "U" shaped dinette/couch, 59 interior and exterior mods to date and still adding
I use 2x6's and then the air bags after which I lower the rear jacks for stabilization and can get another inch or so of leveling out of them. For an indicator I open the door halfway and let go. If it stays there I'm perfectly level (or close enough)
1994 Lance 990 on 1997 F350 PSD Dually "Rhino Haunches"