Hello, Becky,
Oh my goodness, 17 days until your 3rd trip!! To give your daughter a beach experience, my first thought was to visit
Disney's Beach Club Resort as it is themed from top to bottom with a beachy-feel. You don't have to be staying there to visit, but you may find it easiest to consider
dining at the resort to truly experience it aside from actually staying there. A favorite spot at the resort is
Beaches & Cream Soda Shop, which captures the nostalgia of an old-fashioned soda shop. The other thing about the resort is the pool, which is truly like a beach. It has a large sandbar area for children to play in, a lazy river, and even a sand bottom pool. While the pool is restricted to only resort guests, you can still walk alongside it and see al the different features. You could also do an internet search for
Get to Know Stormalong Bay at Disney's Yacht and Beach Club Pool Area to read a detailed article on the pool. It could be your next resort destination for your next trip!
Of the two water parks, I think
Disney's Typhoon Lagoon Water Park is the "beachiest" of the two. The Surf Pool has some pretty intense waves that are an absolute hit with my sons. In fact the waves are so intense you can even take surfing lessons at the water park. You can also actually scuba dive there at Shark Reef. If you'd like, life jackets are complimentary at the water parks; you'll just need to leave an id like a driver's license.
I hope these give you a few ideas of how to bring the beach experience to your daughter. Wishing you a magical trip! -Kara