Sorry for the double, but long posts on a tablet get burdensome.
One thing that I've noticed with hobbyists giving presentations (myself included
), is that they get tied up in the minutiae of gear and details, and quickly lose the audience. A broad overview, and letting the audience guide the rest of the discussion with questions and comments, I've found to be a much better, and easier, method of giving these little introductory talks. 60min of presentation, and 30min of Q&A is a pretty decent ratio IMHO.
Lots of cool/pretty/exciting photos in the background can help spark interest much quicker than listening to somebody go on about the benefits of down vs synthetic sleeping bags.
Personal experiences (stories from the road) go a lot farther in keeping folks tuned in than pulling a bunch of stuff out of panniers.
This should be
fun above and beyond all else, for you and your audience. Keep it light, and show the folks how much gratification they can get from cyclotouring.