Safety, Courtesy, Show and Efficiency! I don't know what it is, but every time I think of the Keys to the Kingdom tour, I feel the need to shout that.
I went as a solo in May this year, and my visit was the same as jordgubben's- Jungle Cruise, Haunted Mansion, Columbia Harbour House for lunch. Since I was by myself, they seated me with a nice couple from Chicago. There was coffee available before the tour, and we all received a bottle of water before we set off.
I didn't feel nearly as tired as I thought that I would after all of the walking, but it's really not that much more walking than I'd be doing at WDW, anyway. The only tricky part for me was the stairs that we took a few times. I have bad knees that like to give out at the worst possible times, so going down stairs is always a leap of faith for me. It was worth it just to see all of the sights backstage- the insides of floats, cast member payday, the big, roaring dumpster. I'd go on, but it would be a breach of the honorary cast member oath.
There was an e-night that night, so I rode on HM about five times to get a better look at what we discussed on the tour. The entry that the tour took on the HM is also used as the disabled access. I think I was the only person on the tour who'd seen it before.