Yeah, have done a little of this in the past--to both Cub and Girl scout troops, w/ their leaders present, but these have all been to fairly young kids (age 9-10-11 or so). Like u say, there's a lot of what one can talk about depending on their interest, age of the scouts, etc. If I'm doing it under the night sky, I'll usually do a thing on some of the basic, easiest to identify constellations, pointing out how to find Polaris--the "North" star using the Big Dipper's stars, etc, and a few of the brighter stars visible to the naked eye at that time of year and their names, and maybe a bit about them, like that one's a huge red star, a 1000 times larger than the sun, etc, etc. If you have a green laser pointer, that's good to use for this. Then usually some basic things--I try not to assume very much w/ a new group/individual--like "and of course, all the stars and planets--oh and point out any bright planets that are visible then too--rise in the east, set in the west due to the earth's rotation, but some stars and constellations never set due to their position in the sky--the circumpolar stars/constellations--with everything seeming to rotate around Polaris (which is why it's called the "North" star to us in the northern hemisphere, etc., etc."
You can also mention the types of telescopes--again especially if you have one of each type--reflector, refractor, and compound--to show them--and maybe give them some idea on the relative merits of each, the relative cost of each--if they don't ask you that right off, which most times someone will. Then time permitting, and if you are into this yourself, you might mention some of more modern "aids" that are available to just about everyone these days, to help locate and identify stars and constellations, planets, etc., in the sky, like the various smartphone and tablet atlas or planetarium programs, etc.(and/or if you have some "old-fashioned" paper-based star atlas, you can show them how we found things in the "old" days, vs. what can be used nowadays with the smartphone atlases, etc.).
Again, a lot of leeway for what to do. I usually try to start off by asking everyone present what their level of knowledge about astronomy is, what they know about the night sky, etc., etc., and take it from there. Anyhow, good luck to you!