There is so much to do and see in Central Florida, that you could honestly spend a month there and not see and do everything.
That being said, schedule days that you lounge around the pool, rent one of the boats, go to the water parks... not just Disney ones. Go to IOA and USF, as well as Seaworld, and Busch Gardens, Tampa. Play Mini Golf or for that matter, if your family likes Golf, check out the golf courses at Disney... they do have cut rate times, depending on when you go. Go to Disney Quest, and if the kids are old enough, let them play there, while you enjoy DTD, a nice meal, and Pleasure Island. Spend a day at Cape Canaveral, if you are into the Space Missions. Go to the beach... you've got the Atlantic Ocean to the east, and the Gulf of Mexico to the west. Disney even has a time share resort at Vero Beach, so perhaps you might like to do that for a couple of days?
I envy you having that much time to spend. Enjoy it, and make sure to write a trip report on your return! Can't wait to hear what you decide to do!