Hi, Laura!
There is one magical room inside the Magic Kingdom located inside
Cinderella Castle. However, this very special room is not available to guests. It was used as a surprise overnight for guests back around 2006/2007 during the "Year of a Million Dreams" promotion. Can you imagine being randomly selected to stay in the Cinderella Castle Suite? Wow, that really is a dream come true! It is now closed to the public completely and only used occasionally when Mickey has a VIP visiting his theme park.
However, no worries for your princess, as she will be treated like royalty wherever you may stay! One option is a
Royal Guest Room at Disney's Port Orleans Riverside. These rooms have magical touches that will make you feel like true royalty! You may also consider a Tower Room with theme park view at
Disney's Contemporary Resort. While pricey, you will get the best view of the fireworks from your balcony. From the Contemporary, you are just a quick walk or monorail ride to the Magic Kingdom.
While you cannot stay in the Cinderella Castle, you can certainly dine there! Cinderella's Royal Table is open for breakfast, lunch, and dinner. Reservations are a must! You may also consider
Akershus Royal Banquet Hall in the Norway Pavilion in Epcot. Here you can dine with the princesses at breakfast (my favorite!), lunch, or dinner.
Remind your daughter to bring her tiara - she will fit right in with the rest of the Disney princesses!
Cathy