We did a 2 night MK only stay earlier this year... our meals included over those days:
First Day/Night: Dinner at Ohana
Second Day/Night: Breakfast in Room, Lunch at Columbia Harbor House, Dinner at Narcoose's (Paid Cash for that one)
Third Day (checkout day): Breakfast in Room, Lunch at Contempo Cafe, Dinner at 1900 Park Fare
Between the Dining Plan and the Kids Eat Free, this was a great way to do it... very cost effective...
A couple of things we noticed - our 1.5 year old still required us to buy him food if he wasn't eating the food on our plate... Easier at Ohana and Park Fare... but might have been different had we chosen to eat at say, BOG, and certainly the Quick Serves...
I found myself ordering wine out of obligation rather than a desire to have it... We also didn't have to bring any soda because we had the mugs...
We have a 5 night stay (BLT) and a 6 night stay (AoA Family Suite) planned for this summer... My gut tells me the dining plan will be much less attractive for those trips --- especially with AP 40% off... I may spreadsheet it all out at some point, but that seems like a lot of work... plus the dining plan immediately takes away a lot of flexibility...
My gut tells me, it works best for a short stay if you know what you're doing...