Hi Lisa!
I can certainly relate to preferring to order off the children's menu at times.
Be Our Guest has a wonderful piece of grilled fish that is the perfect size on the children's menu, but they don't offer it on the adult menu. For a Quick Service meal, this is no problem. You can certainly order either an adult or child meal from a Quick Service restaurant.
Table Service restaurants typically they do not allow adults to order off the children's menu. However, they are accommodating and if you want a smaller portion of a dish, they can accommodate your request. You will still be charged the full price for an adult meal, or in your case, have an adult credit deducted from your
Deluxe Disney Dining Plan. but you will have your smaller portion and won't have to bring a box of leftovers with you around the park.
May I suggest
Trattoria al Forno, located on the
Boardwalk, for their amazing pizza. Also,
Flying Fish is delicious and I found their portions to be reasonable and not too heavy. I had the scallops, and received four, perfectly cooked scallops that were delicious.
Magically,
Stacy