I went to the Boeing factory for their tour in 2014 and went there from Seattle by bus. There was a 10min walk to the entrance from the bus stop.
There were a couple of smaller museums around the airport but were not accessible by bus.
I enjoyed the Museum of Flight so much it took me 2 days to see it all. At the time, you could pretend to do shuttle training (at a cost) and practice an escape via a rope.
I did an epic aviation tour of the US in 2018.
The other notable bonus in Huntsville was my AirBnB host was a former NASA rocket scientist. He was fun to talk to.
Other places I visited while in Florida, Fantasy of Flight (took a flight in a Stearman too, almost landed it but there was a bit of a knack and my instructor took over at the last 2 feet), American Space museum (tells the story of the space program with more interesting tid bits) in Titusville and Valiant Air Command with flying aircraft (like our Temora museum). Also, notable but possibly closed is Wings of Dreams, near Starke (you'll have to drive). The owner collected surplus Space Shuttle things including the Shuttle's guidance and navigation simulator in pieces, the white room from which the astronauts boarded the Shuttle, the external tank trailer and the bus that the astronauts get into when they disembark from the Shuttle. I really likes sitting in the flight deck. The panels are not hidden behind perspex so you can flick real switches and everything!
KSC - I stayed in Titusville for a week. I stayed in an AirBnb and the other two tenants worked for NASA and Blue Origin. I gave myself 4 days at KSC, so got the season pass as the parking included was a good benefit besides the included tours. I also paid for extra VIP tours included going to the missile museum that you can only access through the tour. My meet the astronaut was Jack Lousma who gave us a private tour of the complex similar to the public tour but to a few extra places. He was an excellent tour guide and added extra personal stories too. We had lunch with him and notable were the cool shuttle shaped butter for our bread. We had an official photo with him as part of the package but as the the tour progressed, we could take our own pictures with him at the photo spots on the tour eg. outside the enormous vehicle assembly building. So no, he wasn't some actor in an astronaut costume. There probably is this for the kids during the day. There was another meet the astronaut session in a lecture hall where different astronauts on rotation go to present what they do and you can ask them questions. The lady I listened to worked on the ISS, I had a photo taken with her, with official photographer but I also gave him my camera to take a photo. I was happy with my own photo and didn't buy one.
The presentation of the Shuttle program was fantastic and impressive. I won't spoil the ending but it was worth it. Yes, Atlantis is displayed as in orbit. Gorgeous. You do see it rather up close.
Should you decide to go to a rocket launch, even though my season pass allowed me on the KSC grounds, I would avoid it and find another vantage point. The queue to get from Titusville or from the south, on a single road into a single car park at KSC took 3-4 hours for what would be a 10min drive with not traffic.
Seeing the Valkyrie would be another trip in the future for me. I can see why that's a goal for you.
Is the B36 with its pusher props interesting for you too?
I drove a lot on my trip, taking flights where distances were too great. Hire car costs added up to a lot given my month long trip. It was more about time as well as convenience.
Do you have an EAA membership. Some museums are covered by the card. Eg. Space and Rocket centre in Huntsville, Florida Air Museum. There's a couple in Los Angeles also, if that's on your itinerary.
www.sdairandspacemuseum.com
