Hi Tiffany,
What a great cousin you are to your little cousin! I love that you are planning a special trip with her!
If you are not planning on surprising her, I recommend that you and her spend the day planning your trip. Seven year olds generally like to know what is going on. My niece is about the same again and she loves planning big trips and had a ball helping us plan our trip two years ago. Just being in the parks will keep her busy and entertained.
Magic Kingdom is a must and the new Fantasyland is a super fun place to go. This can definitely fill one day or even two. You could do the
Sorcerers of Magic Kingdom which is a fun scavenger hunt through Magic Kingdom. You may just want to concentrate on Magic Kingdom this trip and then add another park on the next trip.
You may want to plan a special meal especially if she has been to
Bibbidi Bobbidi Boutique. Most little girls like to show there new look around the parks. You could do a character meal or take her to a restaurant that serves her favorite food.
The other thing children tend to love is swimming in the Disney pools. If you are planning a trip to the pool, make sure it is before your trip to Bibbidi Bobbidi Boutique so you do not ruin the hairdo.
Wishing you a magical vacation!
Beth