Hello, Connie!
You must be so excited to make your reservations for your family trip to Walt Disney World in March! Woo hoo!
Regarding your Advanced Dining Reservations, keep in mind that the PDFs which list those restaurants that are currently participating in the Dining Plan are not final versions as of yet. Basically, all of the restaurants in the parks as well as the Disney-owned and operated resorts typically end up participating in the Dining Plans. As of 2012, all of the Table-Service restaurants at Downtown Disney also participated in the plans. However, many of these locations are privately owned and operated; as such the agreements for each restaurant may not have been finalized at this time.
If I were you, I'd look at the
2012 Dining Plan PDF in order to better judge what the
2013 Dining Plan list may eventually look like. Of course, there may, in fact, be some difference between the two, but you'll have a more accurate understanding of the number of restaurants which will most likely participate in the plan as of the 1st of the year. Next, I'd book those restaurants which I think our family would most enjoy (of those which are listed on the 2012 plan), keeping an eye on this document, or calling (407) WDW-DINE from time to time, just to see if any of these restaurants have been added to the Dining Plan.
Of course, you could, instead, book only those restaurants which you know are on the plan right now, changing those reservations when the other restaurants become available.
Rest assured, many more restaurants will surely be added to the 2013 Dining Plan as we near the end of 2012. Have fun making your selections, and be sure to send more questions for clarification if you're at all unsure! :-)