I am not sure how far you want to travel, but Arthur Ave is about a 10 minute drive along Pelham Parkway and there are plenty of great food options there. I would suggest a sandwich at Mike's Deli in the Market and some dessert at one of the many pastry places in the area.
If you want to stay close by, you can drive to City Island and get some fried food at Johnny's for a great price. City Island has plenty of restaurants, but Johnny's is the most casual.
I haven't been to the food pavillions at orchard beach in a long time, but it's fairly standard stuff. Chicken fingers, hamburgers and such. There is also a stand that serves spanish food and always has a line, but I have never checked out.