I have seen where people take water bottles in their backpacks and all so I assume that's okay. What about taking small snack bags or PB&J sandwiches for the kids? No problem? Thanks.
We take snacks and drinks in every time. Each person in our group has a small bag (fanny pack, camera bag, small backpack). We fill with snacks, candy , mints, breakfast bars, PB crackers...whatever that person wants. For drinks, we have juice boxes, small gatorades, and water (and the little mix-in packets).
When the kids were smaller the snacks were a lifesaver when waiting in line. The kids would just pull some smarties, a lifesaver, or a snack out of their pack and munch away!
It also helps to keep the grumblies away, allowing us to eat a later lunch (around 2-3 PM), and making lunch our big meal of the day.
Hope that helps!
As long as it fits in your bag you're all set! We used to pack a case of water in a "water suitcase" on our trips to save money on water bottles! It would then turn into a souvenir suitcase!!