We always stay at the Residence Inn on Astronaut Blvd. It's not on the beach, but it's close to port. We just drive to the beach if we want to go there. If you're going to go to Kennedy Space Center you'll want to head there as early as possible the day before your cruise so you can see/do everything. I'd honestly recommend spending two nights before the cruise so you can get to your hotel, check in, go to the beach that afternoon/evening and then head to KSC as soon as it opens the next morning.
If you get the right room, you can see the VAB at KSC from the window of your room.