The wheels and skids on the back of the RV may do more harm than good. They actually lower the point of contact which may put more upward pressure on the rear of the RV.
A better solution is to go in at an angle which reduces the apparent slope, kind of like going up a steep hill by walking across the face of the hill at an upward angle.
Another good solution is to use long planks laid in the driveway to extend the slope further out, thereby reducing the angle of the slope.
The best solution is to redo the driveway with a shallower slope, however that is mucho work and expense.
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
2017 Airstream Flying Cloud 23FB