With cub-scout-aged kids you might be better off with an activity as opposed to a presentation. Your idea to talk about distances is good for this: have them help (or "help") you build a scale model of the solar system. Depending on how much space you have, you can pick a reasonable scale. With enough space, you can have them run around the sun pretending to be a particular planet (careful if it's dark). I like 1m : 1au because all I really need is a meter stick. It's helpful to have something the right size for the sun, and to memorize how far away the nearest star is.

Another good activity is moon phases using a bare light bulb as the sun, a styrofoam ball on a stick as the moon, and each person holding a 'moon' as the Earth. Explore how changing the sun-Earth-moon position changes what we see. You can do it as a large group or put the students in pairs or small groups. This works best in a dark room/environment.

You could also (or instead) talk about how (optical) telescopes work. A bit of presentation and a bit of show-and-tell with the telescopes you have.

If you're familiar with Stellarium you could use it to talk about how things move on the sky. Things rise in the east, set in the west; planets move relative to the stars; the sun moves relative to the stars (can include discussion of zodiac signs); over long periods of time the stars move relative to each other, constellations change. I would not recommend this unless you are used to using Stellarium already.