Hello Michelle!
Sounds like you are on the right track by planning a royal visit to
Cinderella's Royal Table. Please be advised that the restaurant will be closed for maintenance from January 5, 2015 until the spring. If you plan to visit during it's closure, I recommend that you make a reservation for
Akershus Royal Banquet Hall inside Epcot Theme Park. Located at Norway in World Showcase, it is actually my favorite Disney Princess dining experience. Please keep in mind that reservations can be made 180 days in advance of your trip, and I recommend you call immediately when that window opens. Especially with the impending closure of Cinderella's Royal Table, reservations are sure to be filled right away. Call (407) WDW-DINE.
Princess character meals typically last about an hour. After you get your photo taken, you will dine and be visited by the Disney Princesses at your table. In my experience, that is a good guideline for the length of time to allow for the experience, give or take.
Thanks for stopping by the Disney Parks Moms Panel.
I wish you a truly magical vacation.
-Jacqui