I have parked my coach full time at a campground. The spot is not level and on one side I need to lift the back right side up 6-8 inches and the left rear is 4 -6 inch. I was putting wood on the ground to drive up on . My neighbor came over and said I don't need to put wood under all four drive wheels just the inside wheels. I thought it would be better to put wood under all four drive wheels.