If your toddler is a typical toddler, the good news is that they don't require a huge meal...just little bits more often. Also remember, while in the non-Disney world it may be considered tacky to bring "outside" food into another restaurant that is NOT the case at Disney. When my girls were young we'd often stop and get them a hot dog or chicken nuggets and then head into a sit down restaurant for the adults. As teens they may still want a different CS than the rest of the family, so we just bring in a CS meal from where they want to a CS the rest of us want. Think of it as a big food court, lol.
Anyway....there is fruit to be found in a lot of different places....vegetables are a little harder, but NEVER hestitate to ask a CS or TS what they can do for your little one. If they have veggies in their kitchen, they'll make something for the child. Just as Disney is wonderful about accomodating to the best of their ability the eating requirements of adults....they probably will go MORE out of their way to do it for kids. Obviously this is easier at a TS, but if a CS has a dish with veggies in it, they can possibly give your toddler JUST the veggies because they have them in the kitchen. Always ask.
Here are a few choices:
Main Street has a whole fruit market. Pineapples, grapes, mangos, apples, oranges, bananas. You could always pick up a few items here to take to the restaurant that the adults want to eat.
Toonup Treats in Toontown also has a very large selection of fruit items...grapes, pineapple, apples, mangos, watermelon.
Bengal BBQ has a vegetable skewer and a fruit cup.
French market has a garden salad. Also a pasta/veggie gratin dish. You might be able to ask them just for the veggies without the cheesy pasta.
Harbour Galley has a fruit cup.
Plaza Inn's childrens meals comes with a fruit cup. Also they sell whole fruit.
Pluto's Dog House has a toddler meal that includes apple sauce, so you may be able to get just the apple sauce.
Rancho del Zocalo has fresh tropical fruit.
River Belle has a "Becky Thatcher Fresh Fruit Plate" at breakfast, as well as ala carte fresh fruit.
Tomorrowland Terrace has a fruit platter that includes a muffin and yogurt for breakfast. At lunch their toddler meal has applesauce.
Village Haus has an apple and cheddar salad that has two kinds of apples, dried cranberries, raisins, cheddar cheese and greens. It comes with a yougurt dressing that you can ask not be included.
Blue Ribbon Bakery on Main Street sells fresh fruit.
Clarabelles in Toontown has a fruit salad. Also a fruit and yogurt parfait.
Troubadour Tavern has corn on the cob. I've asked for a knife to take the corn off the cob before. They also have a wonderful brocolli and cheese baked potato. And whole fruit.
Moving over to DCA there are a few less places, but the choices are still there:
Baker's Field Bakery has whole fruit.
Hot Dog Hut has corn on the cob
Lucky Fortune Cookery has edamame and mango slices. SIDE NOTE: Someone else was asking about the kids chicken...this place has teriyaki chicken and rice on the kids meal.
Fairfax market has grapes, watermelon, apples, mango, pineapple. Again, this would be a good place to grab something for the little one before heading to the adult choice of restaurants.
Schmoozies of course have all fruit smoothies....yeah a lot of sugar, but perhaps a treat that your fruit loving kid would enjoy that is at least healthier than some other choices.