If you've decided to stay onsite, you may want to consider visiting the resorts during the holidays. Not only are they all decked out and looking lovely, but many of their restaurants are often far less crowded than what you'll find at the theme parks, and some of them may be a little more affordable than sit downs IN the parks. The ones that come quickest to mind is to eat at the buffet restaurant at Fort Wilderness (Trails' End - if you're in the MK, there is a ferry to get you there, and it's often the cheapest sit-down meal on property) and the diner at the Poly (Kona Cafe, accessible from the MK via monorail), Beaches & Cream at the Beach Club (a 5 minute walk from the "rear entrance" of Epcot called International Gateway, but sadly do not take reservations) and Picabu at the Dolphin (also close to Epcot).
Knowing these restaurants might also be invaluable because at WDW there are many counter-service restaurants, but certainly no such thing as "fast food."
There are many attractions with wait times shorter than waiting on line to order a burger at Cosmic Ray's during peak times. You may find that your mental state will be more recharged by taking the few minutes to get something outside of the parks (but on WDW property) than it would be to try to scream your order at the counter-service clerks, followed by the maddening attempt to find seating for everyone. I know that it's tempting, once you're in the park on a busy day, to want to hunker down and stay - after all, who knows if you'll even be allowed back in if it's that busy? But unless you're all wired on caffeine and have snacks on your person so you can delay actual meals, I think it's always better to get away from the maddening crowds for a few minutes and during the holidays, that often means getting out of the parks. Period. Go to the parks early, pack some fruit or cereal bars, hit the attractions until there's little room to move, then take Disney transportation to another resort for lunch. If you're feeling refreshed after lunch, go back to the parks, otherwise, take a bus to Downtown Disney for a little shopping then go back to your resort.
Of course, you can always go back to your resort for meals, too. Having never stayed at a Value, perhaps others are better to judge, but considering how many rooms there are, I'd suspect the food courts there can get quite overwhelmed, like the theme parks. I know staying at Riverside during Spring Break, the food court could be maddening at all times of the day, and while that's a moderate, it's size is on par with the Values. If you're staying at the Values, you may want to consider springing the extra couple of bucks a day for a small refrigerator (or have a cooler you can keep throwing ice in during your trip). Still stock up on cereal bars (or actual cereal, if you have room for milk in the fridge and get individual containers or buy disposable bowls) and fruits, so you can get to parks early. If you prefer not to go this route, really consider making reservations for restaurants as soon as you're able to do so, and do your best to avoid the rush.
