Parking camper on sloped driveway

You would not want to use it like that. First off you'll wreck the fridge.

Actually, 4" high in the front is well within the operating limits of the fridge. The operating limits are usually 3* side to side of fridge (usualy back-front of camper) and 6* front to back of fridge (usually side-side of camper). Someone did the calcs and that equates to about 8" difference between the front wheels and back wheels and also about 8" difference between the left wheels and right wheels.

If you look at the tubes in the back of the fridge and think of water flowing through them, you want to be level enough where the water doesn't puddle in any of the lines.

And actually, 4" off really isn't that bad to use the camper. I've had it that far off before for overnight parking lot stays and didn't have any problems rolling off the bed or things sliding off the stove while cooking. My biggest problem was feeling a bit off balance.