If you're staying on Harbour, head over to pizza press for lunch or to grab a late dinner when heading back to the hotel. They are open late and their pizza is actually quite good and cheap as well- $10 for a pizza that easily feeds two people.
We loooove Pizza Press! We usually grab a couple pizzas for a late night nibble. Do rope drop to noon-ish the following day, then go back to the room and have leftovers for lunch and to rest. So good (and I totally eat it straight out of the fridge, lol).
Try to find a hotel with free breakfast, or bring your own breakfast stuff to eat in the room. Even if it's just bagels or granola bars, it's enough to get you going through the first few hours of the day.
The coffee in most motel rooms is pretty terrible. We bring the freeze dried coffee packets, similar to Via but much cheaper - about $10 for 50 packets at our Asian grocery store for the kind that already have cream and sugar in them, and cheaper for plain. It might not work if you're very particular about your coffee, but it's cheaper than going to Starbucks every morning, and it's usually better than the stuff provided in the room (as noted above you should be having breakfast at your hotel anyway!)
As others have mentioned, there are meals that you can share, like the Fried Chicken at Plaza Inn. This doesn't work for us, mainly because we are absolutely starving after walking around the parks all day! But it can definitely be done.
I carry around a collapsible water bottle, much easier to carry around when not in use. There are several filtered water stations around the park, and Anaheim tap water is very drinkable. You can also ask for a free cup of ice water at most food locations.