Believe it or not, there is a place called Disboards that covers this - BIG time
http://www.disboards.comOne HUGE tip - you can buy water bottles with carbon filters in the bottle (Britta USED to sell them, but it turns out they were violating a patent). Get one for each family member - the water at the water fountains in the park is GROSS, but cold. If you use the bottles, it's great. Now Disney charges like $3 for a drink - you will save a FORTUNE bringing water bottles
They never stopped me with a limited amount of snack food, or with my small pocket knife
Disclaimer: I work for a company owned by Disney, but have NOTHING to do with the parks, except to have gone there 2x in the last 10 years