The easiest and most versatile thing I have used, and this is old school, are 2x6 boards. With one 8 foot board I can make 2 three foot boards for the wheels and one 2 foot board for a jack. Cut each end at 45 degrees to ease backing onto and you can build ramps, runners, stable platforms, whatever you need. Last year, to park a 41 foot BayHill fifth wheel, we used all of my boards plus an 8x8 on the downhill side and dug in the uphill wheels about six inches. That got me to within four degrees of level side to side. We then built platforms under the jacks and used the autolevel to level it. A Jayco would not have leveled, but the hydraulic level up system did it. Afterwards I had to build a set of steps because the bottom entry step was mid to upper thigh on me. It worked, but I can't say I recommend that procedure for daily use. I probably should mention that I grew up blocking grave sites in West Virginia for funerals using concrete burial vaults, so blocking heavy objects at extreme angles is not that big of a deal for me.
2000 Ford 4x4 Crewcab Dually 7.3 PSD
2015 Seismic 3712
2013 Jay Flight 32BHDS (sold)
2009 Jay Flight 31BHS (sold)
2005 Jay Flight 27BH (sold) - probably my favorite