Don't be too disappointed if you can't get the ADR's you want this late in the game but maybe you will! You might have to think "outside the box" and do some ADR's that are very good but overlooked by the majority of the people. For instance The Grand Floridian Cafe, Kona Cafe, perhaps if your staying at a resort that has a sit down restaurant, Wolf Gang Puck Cafe and I know there are a million others I'm not thinking of! Also if you really wanted character dining this late in the game you might have to be REALLY flexible on the times to get the ADR's! Anyway, no matter what you will have a great trip it's Disney after all!
First off, a WDW vaca should be more about the entertainment (rides, shows etc...) than the food. Secondly, there's a wide assortment of counter service foods available at EPCOT, MK, and AK (burgers, salads, dogs, pizza, salads and bbq, for starters, not to mention World Showcase, and Sunshine Seasons in EPCOT) also, you could get lucky with a walk up for an early lunch or dinner (a late supper may not fly w a 5 y old) also, if staying onsite, don't discount the resort food court for lunch (if leaving the park for a break, or dinner if returning to the resort early (laundry night 
) 
There are also plenty of resort TS that may have space for walk-ups, or day-of ADR, if you call that morning, or the day before. Have a great time, and don't expect to see **everything** ((no one ever does on their first couple of trips, thats the fun of planning another!)) 
