The first thing to do here is to go on the KSC bus tour. They start early and run every 15 minutes. There is also plenty of wildlife to see along the way, and plenty of exhibits throughout each of the stops. The bus driver can be good if you get the right one. Make sure that you give yourself enough time for this trip since it took us around 3 hours and we didn't see everything. There are 3 stops along the way. Those stops include...
(1)LC-39 observation gantry-where you can see some of the launch sites
(2)Apollo/Saturn-V center-touch a real moon rock
(3)International Space Station Center-see them working on the next space craft going to the International Space Station.
Upon returning to the main complex There are two IMAX theaters. One narrated by Tom Hanks (Magnificent Desolation) and the other by Tom Cruise (space Station 3-D) both are good and about 45 minutes long each. Get there early and try not to sit too close for the 3-D effects are better at a distance. P.S. don't forget the popcorn.
Mad Mission to Mars is definitely a kids show and has really limited seating so get here early, and get a seat because the kids have a great time and so will most adults.
The Rocket Garden has an area where the kids can play but better than that they have some of the large rockets. It is AMAZING and it's where you can walk across the same Gantry that Neil Armstrong walked before he went to the moon. Also get inside some of the capsules that 1, 2, or 3 people would get inside. Just remember that they chose men that were about 5'8" or less just to fit the spaces. Twice a day they also have a walking tour with a guide that is fairly informative, but is a little dry and the kids might get a little bored.
Launch Status Center has a lot of info but while we were learning about outer space the kids were getting their booklets stamped. It keeps them somewhat interested but not for long.
Launch Status Center gives an update of upcoming missions but nearby you can see a replica Space Shuttle and the wall of light where those who gave there life in the quest of space.
Maybe best of all could be to listen to a real live astronaut talk about their missions, being able to ask them questions and getting your photo taken with them. Our astronaut had gone up on 4 missions including an untethered space walk and working on the Hubble telescope.
The Robot Scout exhibit is one that is somewhat boring and could easily be passed up.
There are other exhibits and plenty of shopping so leave time for that as well.
There is so much to do here that you will be glad that you can come back the next day for free just make sure that you get your ticket validated as you leave for the day.