We did the "Keys to the Kingdom" tour April 29th. Brad, our tour guide, was fantastic. The tour lasted about 5 hours including a lunch break at Columbia Harbor House. There was a lot of history and trivia which I can never get enough of! We got our own boat for Jungle Cruise, but instead of the usual narration, Brad told us about the ride: when, where, why, and how. We also got to enter HM through the rear entrance (used for celebrities!) and rode the usual ride. By doing this we missed the stretch room, but it was still cool. We also got to go backstage behind Splash Mountain where they maintain the floats for the parades. It was neat to see them sitting idle, batteries charging, and look inside where the drivers' sit (no A/C for them!). Did you know there is a "hidden Walt" on each of the snow-globe floats? We next went upstairs in one of the Main Street buildings - they all look alike from the rear - where we got to see there are regular offices up there. Then finally down to the tunnels. Again, more neat stories and stuff. Got to see the trash tubes, lockers, more rooms, etc. One neat thing down there is that the lands are color coded and the stairways marked so, when you are in costume, you know where you are allowed to enter onstage. Overall, absolutely worthwhile and fun, plus you get a cool key to the kingdom pin. I don't know the cost, but you can find it on Mouseplanet.com. We used our Discovery Wishes package to pay. Hope I didn't spoil anything for you. GO DO IT!
ps - absolutely no cameras allowed and you MUST bring photo id. Two couples didn't have any and were not able to go - had to reschedule.