No hard sided coolers, outside food or drink (baby food/formula and soft sided coolers for those, and water are ok), weapons of any kind (take the Swiss army knife off the key ring and leave it at home), clothing with vulgar displays or obsene language (it is a family place after all). Basically, just use common sense when figuring out what to take into the parks. They do search your bags before you enter the ticket plaza. If you bring a hard-sided cooler and food/drink they'll direct you to a locker area to store it in and a nearby picnic area where you can eat the food.