Check out
www.birthdaypartyideas.com to see what great ideas you might find. Here are my suggestions...
1. Grand entrance...since Disney is so big on using the balloon theme in their commercials this year...why don't you make a balloon arch. They are super easy to make and pretty inexpensive! Then you can get balloons to match your color theme. Google "how to make a balloon arch" and I'm sure you will find some ideas for how to make one. Again...they are super easy and cheap if you make it yourself. You just have to buy the balloons and rent a helium tank.
2. I'm big on having favors for your guests. You might consider having a candy buffet. Send me a pm with your email and I can send a document I set up in word with some great pictures and ideas for one.
3. Not sure what kind of a budget you have for your party...but check out this thread for a centerpiece idea that is super inexpensive but looks really good on tables...the pictures don't quite do it justice. Then if you wanted you could have a bunch of balloons coming out of the center of it as well to give it some height.
http://www.disboards.com/showthread.php?t=2265931
Another idea would be to see if you can't find the "disney castle" and have it as a centerpiece on the tables. At Hobby Lobby in the wedding isle they have silver Cinderella Carriages Photo Holders in case you can use them in some way. Get them when their wedding supplies are 50% off. Also, they have a nice silver cake stand that you can get for 50% off with a weekly coupon if you decide to go more elegant with the cake.
4. cake: have you seen any of the cakes for the disney challenges that they do on the food network? They are pretty amazing. Again not sure what your budget is or what type of cake decoraters live in your area. You might try googling food network and disney cakes to see if there are pictures of them online.
Maybe you could have the cake designed like Cinderella's Castle
If I think of anything else...I will try to remember to post it.