I have not read all the suggestions, but live on the East Coast. East coast has an ocean and more fun to play in, but with with an 11 year old to entertain....and not minding a drive.....I suggest do both the Gulf area and the Atlantic. You could even do day trips to either beach from Orlando. If you spend time in Orlando check out Sea World at Christmas. They have special shows and the decoration for the holidays and NYE concert and fireworks are spectacular. For the DH you could go to a Magic game. Even if you are not a big BB fan there is so much going on during the game you almost forget to watch the game . The mascot, Stuff the Magic Dragon, is cool and keeps the crowd entertained.
I would even suggest Island Grand at Trade Winds in St. Pete beach if you head to the Gulf because it has the big slide right on the sand. St. Pete would give you access to everything in Tampa from museums and restaurants to Busch Gardens for entertainment for a few days. BG is a lot of fun over the holidays and has good fireworks on NYE . There is shuttle to an island with lots of shells to let her get some nice shells, also. It is a fun excursion.
Then head to the Space Coast for a rocket launch(going up almost weekly now) and check out the space center. Canaveral National seashore is pretty cool and you might see a rocket on the launch pad from the beach. There is a nature drive Black Point Nature Drive at the Merritt Island Wildlife refuge that is really cool also. You will see lots of birds, aligators, manatees and experience Florida marsh and coastal hammocks.
Taking some surf lessons in Cocoa Beach might be a fun experience for you all. Any beach on the space coast will have larger waves than the gulf and a different type of sand, but they are fun. Usually it is still in the 80s during the day still at Christmas here, but they are predicting a wet and rainy winter this year so it may be cooler at Christmas. Usually local surfers don't wear wet suits till after Christmas, though.
