We did this tour last summer. My husband owns a steam engine, and is very fond of trains. After I did the Keys to the Kingdom Tour the year before, I was really wanting to give my family the opportunity to see some behind the scenes magic. I'm pretty sure I booked it about 180 days out, but I could be wrong. I did book it as soon as we decided what day we would do it.
It was my DH, DD12, and myself. We had a car for this trip, so we parked at the Contemporary and walked over to the MK. We probably got to the MK about a quarter to 7 (the tour starts at 7:30, and I was nervous about being late). It was amazing to see the gates of the MK completely empty! We were literally the only guests there for about 20 minutes, and it was just too cool.
The tour started right on time, and our guide was very knowledgeable. It was a very informative tour. It was neat to go to where they work on and store the trains. If your husband likes trains and steam engines, he will enjoy this tour. If he knows a lot about trains and steam engines, he might notice an error or two during the tour like my husband did. It didn't ruin the experience for him at all, it happens. I couldn't imagine having to remember all of that information!