Best thing I found for this age group as well was a water table they would spend hours. All you need is a couple inches of water & you can buy plastic water bins at the buck store, set up a few and let them go crazy. The bins make it easier on the few that might want to sit in it! This way it’s too small! LOL

Painting the fence is really a good idea as well. Fill a plastic pail with water & paintbrushes and let them go crazy!

Blankets I find are great as well as play tents! Ikea has a good one for $20.00!

Mine last year were this age and they loved the ride on toys as well as the sandbox.

I hated the sandbox because they always brought sand and put it in the water table and it was just plain messy!

Oh and bubble, bubbles and more bubbles!