At 4 y.o., my kids were worn slap out by dinner time, so we'd head back to the room and eat dinner at the hotel. You could always do dinner in your room, there's lots of microwaveable dinners you can quickly fix.
We take baggies into the park to split snacks like popcorn, candies, cotton candy. You can split a lot of adult meals and there will be plenty for you both. At Rancho Del Zocalo's, their entrees are huge and you can add a side like tortilla chips to make it even bigger. The Plaza Inn chicken entree is large enough to split also. If you ask at any counter service, you may be able to add on a side dish. If you're not all that hungry, there's Mickey pretzels and hot dogs are cheaper than an entree, too. You can get a free cup of water at any counter service.