As some one mentioned earlier, if you have any of the other discounts, the dining plan may not work (especially the free one). We had booked on the bounce back offer of 25% off. A few weeks ago, we received a few different "free dining" offers. When I called, it would have cost me an extra $400+ for 2 adults and a 3 year old - to get the free dining for 7 days. Not worth it in my eyes!
We have never done the dining plan in the 18 trips I have made. We don't eat enough sit-downs for it to work out. Next year, when the offer the counter service - it might work! In the 7 days of this upcoming trip, we will do Chef Mickey, Pooh at Crystal Palace, and DH and I only at the Clam Bake at the Beach Club. The rest of our meals will be counter service. I UPS a box of snacks (cookies, chips, Entemanns donuts and donut holes)and other essentials (non-refrigarated milk boxes, diapers, water, soda, etc) down ahead of time and when in the room we use those. Bring a collapsible cooler to fill with ice and you are set (if in a Value).
Breakfast - we hit the food court. DH, myself, and DD3 share 2 adult meals. We will up our one refillable mug.
Lunch - depending on the park we are in, we pick one of the counter services there. For example, at Pecos Bills in the MK, we order a Chicken Wrap, a burger, and share an order of fries. DD gets a kids meal. One thing to mention here, is you DO NOT need to order the "meals" - you can order a la carte - like I said, we only order one order of fries.
Dinner - the 4 nights we don't have sit-downs, it will be catch what you can as we pass it. We may hit Earl in DTD, or even Giardelli's and have a really fattening dinner!
I am not one for dining in the world showcase. As a matter of fact, I have only eaten at America once!
So, it's all a matter of what you want to bring in with you for snacks, and whether you stick to a schedule. Eat at off-times. Maybe a late lunch, which can result in a late dinner, when there are no lines! This works great with little kids. Let them snack early in the afternoon, so you can delay the next meal!
Enjoy!