I know CS Pepper Market allows take-out. So does the Trails End Buffet. At the Swan, they were less enthusiastic to allow us to do this. We were finally able to get an outragiously priced pizza sent to our room (It was very excellent, not the pizza they have elsewhere - real fresh mozarella, fresh basil, tomato slices) but it was not worth what we paid for it. I think it was around $20 for what I'd classify as a 'small' pizza (around 6 slices)! They said it depends on how busy they are.
The deluxes all have room service, the mods will at least bring pizza until midnight, and I think the values also have pizza.
I don't think I'd want to bring take out from any of the in-park restaurants, as it would take too long, and be too difficult to bring food that far.
One thing you can also do is to get leftovers wrapped. Again, I don't think I'd do this from an in-park restaurant, but many rooms have a fridge - so if you had sandwiches or something you didn't mind eating cold left over from lunch, you could put them in your fridge for dinner for a lot less than most room service would cost.
Plus, most of the resorts have a market where you can get drinks like OJ for a decent price.
Where are you staying?