I bring many things into the park, and it seems I've used everything with one kid or the other. Always have Band-aids, Neosporin, snacks (like Goldfish), ponchos, change of clothes (youngest), refill mugs, Tylenol, Pepto tablets, sunscreen, camera, Ziploc baggies (for water rides), phone, and wallet. Right now we're also toting diapers. It's not that big of deal to bring things in with the stroller, but when my oldest outgrew the stroller, I made here carry some things in a fanny pack if she wanted them--mostly her snacks. Then I just had a drawstring backpack for carrying the mugs, mostly.