One more thought: For a lot of us older folks, the journey is the adventure. For kids, the destination is where the fun starts. Choose shorter routes for kids. And have something fun to do when you get there.

When I was young I was happy to hike---but I would have climbed over Everest to get to a secret fishing spot that had lots of fish.

The rest of the advice here, from Glenn on down, has been terrific. The only thing I would try to teach the first trip is how to build a fire with one match. FUn, easy, and valuable for a lifetime.