Pizza Port, excellent choice Albort! Kid friendly pasta and pizza, salads for the parents or yummy Alfredo. You can buy a whole pizza too. (Pricier than Domino's)
Plaza Inn is nice, HUGE portions. We buy two plates of the chicken meal and share it between the four of us ( 2 adults, 11, and 14 yr old boys) .. and feel overly stuffed at the end.

It's 3 pieces of chicken, mashed potatoes with gravy, green/yellow beans, and a biscuit $12.99. Served on platters! Refills for pop (soda) are free. The only sucky part is seating can be a challenge inside, though we have lucked out and snagged an inside table the last 4 times. Check the left side, most people go to the right.
White Water Snacks inside the Grand Californian is nice, easy exit from DCA (yes, you can go back into the park that way, ignore the signs which say hotel guests only). Made fresh and big portions, adults will be satisfied with child portion meals. Small kids can easily share the chicken fingers meal- BIG pieces and tons of fries. They also have premade salads, desserts, sandwhiches, and fresh fruit trays. Prices a bit less than in the parks, and better tasting too.. DCA has crappy dining options IMO.
It's very peaceful in the outdoor seating area.
If you're really quiet, one of the Disney cats might come up to your table for a treat. (She doesn't like fries, give her hamburger or chicken and she will even let you pet her for a minute. I have had the same white/orange/brown long hair tabby visit me on two trips.. a year apart!)
IHOP on Harbor has kids eat free, but heard they have horrible service... sloooooooooooooooooooooooooooooow.
McDonald's on Harbor, there is a 10% off coupon here. Print a bunch!
http://www.anaheimoc.org/Articles/Archive/Webpage10153.asp
Maybe buy those treat coupon books? Free fries, free drink, ice cream, etc.. I had really old ones from 2002, gift certificates don't expire in California. If you're walking back and forth to the hotel, it's easy to pop in and have a treat on the way..... mmmm ice cream cones!
They do have the dollar menu at that location, it's just hiding behind a freezer.