We're planning to do the same thing - we'll do a couple of special meals and some snacks in the parks but I plan to take our own food for breakfast and several picnics. It does get old to fight the crowds at every meal, not to mention the expense. We're driving down and staying at ASMo so some of my ideas may not work for everyone. But here's what I've thought of so far:
Take "It's Pasta Anytime" spaghetti dinners to heat in the food court micro, bring a bagged salad and have with breadsticks from the food court.
Instant mac & cheese (either made in the food court micro or with hot pot brought from home) and mix in a can of peas and some ham for a one dish meal.
To round out a meal of sandwiches, I will take a few extras like olives, pineapple chunks, cherry tomatoes & baby carrots.
Just before the trip, (if I have time) whip up some homemade treats like fried chicken, potato salad, brownies, pound cake - things that we don't have often and that travel well.
This isn't a meal idea, but something we did last trip that worked well for us - we all went to the grocery store together and each of us picked a few treats (like a favorite candy, snack paks of cookies, etc.). I bagged each persons stuff in a big ziplock bag so that each of us had our own bag of goodies to delve into whenever the munchies hit. The only stipulation was that your treats had to last the entire trip. We felt like we were getting a real treat (especially our ds) and it seemed to cut down on the urge to buy so many snacks in the parks.
Oh, and we all ended up sharing our treats and even had some leftover at the end of the trip.