I did a last minute trip for a night launch and went with Gray line. That was a good idea, as leaving the Causeway was a traffic jam like i'd never seen before. Was nice to be able to sleep through it.
The day was brutal though. I brought a camera,, tripod, and blanket. The tour leaves Orlando in the morning. There isnt THAT much to do at the space center, and we have all day. In 90 degree heat. Lugging my crap around. And not much is both indoors and air conditioned. I ended up camped out in an auditorium where they were playing the film about the Orion project ona loop. I must have seen it 40 times, but at least it was air conditioned.