@SMeustace: I was very fortunate that 1, the show was not very technically heavy (no major scene changes except at intermission), 2, I'd worked with most of the cast/crew & in the space before, and 3, the crew had a tech rehearsal already slated for earlier in the day to clean things when I could come in and learn the show. I arrived with script, pencils, and sticky notes ready. The SM walked me through everything with cues, then the ASM and I discussed how to handle things like traveling props.
I'd say how much you throw at them depends on their familiarity with the show and the space. I was very familiar with the theatre, so some things we could breeze over and get right down to business. If hadn't ever worked there before, though, I'd have needed more info on that front. I also had been able to watch clips of the show online prior to the show and knew most of the cast, but again, without that knowledge I'd have needed more help in that regard.