When leveling front to back most any trailer will have a big advantage over a motorhome because they have so much more travel for that direction. What I can't understand about your post, is you say the driveway only has enough slope for rain runoff, yet you have to raise your rear wheels to get level? Sounds to me like you have a lot more slope than you think. Either that or your motorhome isn't really level to start with. When my motorhome is sitting on a perfectly level pad and the airbags are deflated, the motorhome is almost perfectly level without the jacks. I'm guessing your motorhome must be nose high when sitting on a level pad?