Hi, Margaret!
The
Crystal Palace in the Magic Kingdom does indeed accept the Disney Dining Plan.
With one exception, regardless of the
level of Dining Plan you purchase, this particular Character Dining Experience will deduct one Table Service Credit from each member of your dining party.
The exception, then, is the Quick-Service only plan; because there are no Table Service credits on this plan, it will not cover the Crystal Palace.
Bear in mind that gratuities are not included in the Dining Plans, unless specified. And don't forget to call (407) WDW-DINE to make your reservations in advance.
Have a "hunny" of a time!
See you later, celebrator,
-Deborah B.