I’ve done the Keys to the Kingdom tour. It does tie you up for quite a while, but they feed you lunch. Most of the things they told us I already knew from being a Disney freak, but it was really cool getting to see the parade float area backstage and the utilidors underground. The tour is for the 16+ crowd, though. Strict age limit (though they never IDed me… and I look 12, apparently).
I’ll add that the Segway tour is also for people ages 16 and up.
As well as the big 3-park behind-the-scenes tour.
Wild by Design is 14 and up. It looks really cool. I’d like to do this tour. And not to threadjack, but I’d be very interested to hear what Soundgod though of this tour.