[Cadaverous Pallor]

I don't think we ever had one that serious growing up but pretty close. Will the bottom be rigid? If it's a flexible bottom and you're keeping it there all summer, I'd recommend ripping the grass out underneath it. It's all going to die anyway, and that way you can definitely get rid of small stones, even out the ground, etc. It might look soft and flat but it really isn't.

My mom used to put a bucket of water by the entrance to the house, so you can dip your feet and get rid of the grass clinging to you. We spent a huge percentage of our summer outside in small pools, fun sprinklers, slip and slides, etc because we had no air conditioning.