Thanks for all the advice. I had my first day of it today (4 groups in 1 hour). There were two high school age groups and 2 middle school age groups. I talked through the process from pre-production through performance, then had them ask questions. This kept the 2 high school groups occupied for the whole time...they got it a little more. With the 2 middle school groups, I played a script analysis game that I'd worked out. I had 6 of them read 4 pages the "sad Crachit" scene from Christmas Carol (including stage directions) aloud, and I had another 5 hold up signs I had made, whenever they heard something that sounded like it fell into their category (props, sound, lights, scenery, costumes). With one group, the game went really well, with the other, not as much(but it still took up the time...).
I didn't have my kit with me today, because I forgot to bring it home from the theatre last night, but I'm planning to take it with me next week.