If you buy a case of water at walmart or target, you can freeze 6 bottles each night. Take them with you in the morning when you head to the parks. Each person will have cold water to drink until lunch. Be sure to put them in a plastic bag before you put them in the backpack so they don't sweat over everything. Pack a sharpee and label the bottle cap of each bottle so you don't get them mixed up.
Have an awesome trip!
Have an awesome trip!