In case your sandbox still needs filling, here’s a back-saving tip from Duane:
I don’t know if this one is too late in the season, or if I’m the only one dumb enough to have done this, but I’ve learned on Parent Hacks to never assume. What did you do with the sandbox sand last year? If you’re like me you saved it. Why not? It’s a pain to get rid of, a pain to buy new, and it’s not like there’s anything wrong with it. So here I am with several very large and heavy bags of sand in the garage (moving 1 is a chore, 2-3 would be impossible), and now I have to get it back outside to the sandbox. Solution? Plastic snow sled. Bag of sand goes on sled, drag sled to sandbox, dump sand. Repeat.