There are GF snacks available in the parks and no need to let the CMs at the gate know that you are bringing in snacks. They will just check your bags for glass containers and other hazards. DD12 has allergies to dairy, egg, tree nuts and peanuts and is able to find some snacks, but we always bring in most of her snacks. There are a lot of GF Disers on this board, so you should get more info on the prevalence and variety of GF treats on this board. You might want to contact special diets and ask if they have a link to their most recent GF free offering list. We were able to get links for the dairy free, egg free, tree nut and peanut ones. I hope you have a great and safe time!