Eric:
They've changed it up quite a bit since the shuttle program ended, so I'm not sure what else has changed, but you could easily spend a whole day. The visitor center has some amazing stuff, including the Rocket Park and the space shuttle
Atlantis. The
Astronaut Hall of Fame used to be a separate facility, but all that has been moved to
KSC Visitor Center. Definitely take the bus across to the
Saturn V Pavilion. They did SUCH a good job with restoration. The
Firing Room recreation will take your breath away. Make sure to take whatever "behind the scenes" bus tours they offer. There are things like the Apollo 1 Launchpad, the burial site of the Challenger, and the Mercury 7 Memorial that aren't on the regular tours.
There was also one tour that used to be called
"Cape Canaveral: Then and Now." KSC Visitor Center no longer handles it, now that Cape Canaveral is run by the
US Space Force. They now have a separate museum:
https://ccspacemuseum.org/ I would spend your second day there. You get into the blockhouse that launched Shepard and Grissom and tons of other artifacts from the dawn of the space age.