We bring a small softsided cooler and pack lunch, snacks and drinks. Rent a locker so you don't have to drag it around all day. If you park hop, be sure to keep your receipt and then present it at the next park (they won't charge you twice in the same day, but you will still give them $3 refundable key deposit).
We usually shop and have them deliver food from Garden Grocer. Even if you don't have a fridge in the room, there's tons of non-perishable items that'll get you by. Pnut butter & jelly for sandwiches, the Chix of the Sea tuna lunch (includes the tuna, crackers, etc.), pudding cups, fruit, milk in single-serve cartons that you don't have to refrigerate, etc, etc.
I always make sure to have really nice treats (good cookies, candy, etc) so we don't need to crave anything special - although we still buy ice cream and specialty treats at EPCOT!
We save a ton of time and money doing it this way with b-fast and lunch. Sometimes we even eat dinner in the room. We splurge and have nice dinners at least a few times while were there tho!