Hi Amanda!
Thanks for your question and for visiting the Disney Parks Moms Panel!!
I like how you think regarding accommodations!!!
Disney's Grand Floridian Resort & Spa is my favorite resort in all of Walt Disney World. And there are loads of recreational activities both on site AND throughout all of the other resorts on property, AND at the water parks, including everything from fishing excursions to surfing lessons. Water skiing, at this time, is not one of the available choices of
recreation on property, unfortunately.
May I suggest either renting a watercraft from the marina out back of your resort, or maybe go for some parasailing over behind
Disney's Contemporary Resort, or maybe even some surf lessons over at
Disney's Typhoon Lagoon.
I hope this helps and I wish you a Magical trip!!
Chris