We love KSC and don't get there often enough. My DD even went to Space Camp last summer (while DH and I enjoyed relaxing days at the beach) and she can't wait to go again! I think that the general admission pass, which includes the bus trip, the visitor center, and the Saturn V center, takes the whole day, especially if it includes the IMAX theatre show. The visitor center has a bunch of exhibits including the opportunity to walk through a shuttle and visit the memorial garden, a tribute to those lost in the efforts to explore our universe. It also includes the rocket garden, which has an impressive display of rockets and offers the opportunity to walk across the walkway into a *white room* (the last place an astronaut has contact with humans prior to launch) and to squeeze yourself into the mercury and gemini capsules...and I do mean squeeze! The bus trip takes you past the vehicle assembly building, which is unbelievably huge and out to an observation gantry from which you can see the shuttle launch pads and the "historical" launch sites...those from the mercury, appollo, and gemini missions, as well as the rocket launch sites in use today. You'll also see the shuttle landing area (keep your eyes open for armadillo and gators!). The best is the Saturn V exhibit, which includes several shows and the most amazing thing I've ever seen- a real, full size Saturn V rocket (it was scheduled to go to the moon before the program was scrapped). I don't think a 6yo would be bored at all! We always spend the whole day when we come here. The Astronaut Hall of Fame is also very cool, but you won't have time for KSC and AHoF on the same day. AHF has alot of history to it, with walk-thru exhibits demonstrating different astronauts, the different programs, lots of memoriabilia and souvenirs from different launches and places (like the moon! although at the Saturn V exhibit at KSC you can touch a real moon rock!), as well as a room full of interactive exhibits where you have the opportunity to ride in the centrifuge that is part of astronaut training!
Logistics: About an hour easy drive from WDW area, on highway, can't miss it. There is a pretty decent cafeteria in the Saturn V complex, also food stands at KSC visitors center, all with theme-park type and priced food! There is really noplace to get dinner on the way back to the Orlando area until you get into Orlando. Cocoa/Cocoa Beach have some decent places to eat, also some chain restaurants, but it is about 30 min drive EAST of KSC, not on your way back to the theme park area. Admission is about $30 to KSC, depending on add-ons (like IMAX shows at visitors complex, and they ARE worth it). Call before going (or check online)- security is high if there is a launch going on, even for rockets, and hours or access may be limited/restricted. KSC is our favorite, AHoF was very cool and interesting, and I really don't think you'll have time to do them both in one day.
