There are a lot of ways to cut corners without seeming like you are cutting corners.
I got some deals on Starbucks gift cards, Sams and at BJ's which I gave as gifts during Christmas, I know they carry them year around, you could use them for snacks or breakfast.
Also sometimes Target offers GC deals with the Red Card, I have a friend who is the Queen of this, she know how it really works. So I call her when I have questions.
I sometimes will buy a GC when I am buying grocery, and I save them for trips.
Since your staying off site, I would make a big hearty breakfast, bring in snacks, everyone carry a water bottle you can bring in those flavoring packets to change it up, lunch in the parks, using snacks as needed, then dinner at the condo in the evenings. Hauling a cooler around isn't fun in my book. It was okay when we had a stroller but once that went away we had to rethink that...
Snacks, pick them up ahead of time, cheese crackers, chips, granola/breakfast style bars, the protein ones are our favorite. Those individual cups with cookies, chips, Pringles, goldfish, I like these as things don't get smashed in the back pack. I shop at Publix, and just picked up Bogo on Lances Crackers, and the week before they had chips ahoy and nutter butters boxed in individual serving on BoGo. The more you save now is more towards Disney later on. Also buying ahead of time means you won't have that expense right before vacation.
See if your condo has a crock pot, you can put something on in the morning, and it nice to have dinner ready when you get back.
Check Groupon for deals, Sweet tomatoes always has some promotion going, normally 4 can dine for 22.00 and includes drinks or buy one get one, or something along these lines, pick up pizza or Chinese to take back at night.
I would do research on what you feel you can share at the QS, so that you know what's available ahead of time. Also you can always get a extra side of something if needed, it won't be listed, just ask. For instance when our DD where around that age, we might stop at Cosmic Rays, and get 2 - 1/2 rotisserie meals (13.79 price on Disney app right now) which comes with mashed potatoes and a veggie, but we would order extra sides of mashed potatoes, I don't know the price right now of extra sides, ( anyone know?). We could eat for under 50.00 dollars for the 4 of us including drinks, that about 12.50 a person which isn't to bad. or 3 Chicken Nuggets meals (8 nuggets) ( 9.49 on Disney app right now), around 30.00 with tax, and you can drink water, its free. That's around 7.50 to 8.00 per person which isn't to bad.