Need to raise camper 3"...looking for suggestions

Such a shame to waste all that space under the camper.

I use two pieces of 4X4 to raise my camper with a thin box in between. The box is perfect for hoses, ladder, rope, etc.

I jack the camper up only 1/4" and then slide out the box and the 4X4s. In this way I can then simply drive right out. No need to lift the camper higher than necessary.

If you attach the spacers to the bottom of the camper, you need to raise it this much more to drive out from under.