Hi Elizabeth,
As a fellow Illinoisan, I sure wish we were both in sunny Walt Disney World right now! Thank you for visiting us with your question. Your vacation planning sounds like it's coming along nicely. Cinderella's Royal Table is a very popular dining location so it's best to try to set Advanced Dining Reservations now. Many seatings will be booked as early as 180 days in advance. You can do so by calling 407-WDW-DINE, 407-939-3463 or
online. Unfortunately, there is no flexibility with the table-service credits on the Disney Dining Plan. Your choice would be to use 2 table-service entitlements per person or pay out of pocket for this meal.
If you'd prefer to only use 1 table-service credit but still visit with Disney Princesses, I would highly recommend Akershus Royal Banquet Hall in Epcot (Epcot admission would be required) or Cinderella's Happily Ever After Dinner located at 1900 Park Fare in Disney's Grand Floridian Resort & Spa. It's a quick monorail ride over to the Grand Floridian and although characters are always subject to change, you can typically visit with Cinderella, Prince Charming, Drizella, Anastasia and Lady Tremaine. It's a great use of table service credits!
I would also recommend Advanced Dining Reservations for any of the abovementioned dining options. They are popular, for good reason!
Happy planning,
Sherri