Hello Ron! My daughter, who is 8 now, used to be a very picky eater. She's gotten better about trying things but she still likes the basics.
I think Disney does a nice job of offering a variety of menu options all over the parks. There is enough variety to please adult palettes but there are always a few safe menu items too. I know for a fact you'll be able to find chicken nuggets, hot dogs, pizza and mac and cheese at various location all over Walt Disney World. My daughter also loves the power packs that you can find at some quick service locations, like Fairfax Fare in Disney's Hollywood Studios. These boxes come with prepackaged goodies like carrots and dip, goldfish crackers, string cheese, yogurt and a cookie. My daughter used to eat the cold items first and then save the others for snacks later in the day. Here are some other places you might want to keep and eye out for:
- Casey's Corner in Magic Kingdom serves hot dogs and corn dog nuggets. My daughter likes to order the corn dog nuggets and then pick off the corn dog part - go figure
- Colombia Harbour House in Magic Kingdom serves a child's mac and cheese. Keep in mind this is a more homemade version but my daughter really enjoys it.
- Pizza Planet at Disney's Hollywood Studios serves pepperoni or cheese individual pizzas
- Restaurantosaurus at Animal Kingdom offers burgers, hot dogs and chicken nuggest
If you are really concerned your fussy eater wont be pleased with food in the parks my other suggestion would be to bring your own food inside the park. If I were you, I might heat up a package of easy mac at my resort food court, microwaves are readily available, and stick it in a thermos to keep it warm for later in the day.
I hope this helps give you some suggestions. If you have any other questions, please come back and ask.