Can lost dogs find their way home?

I recently heard a claim that a dog found his way home from being lost on a family vacation. He had escaped their RV in some national park, was given up for dead, yet managed to make his way across the country back to his loving family. Have there been any documented cases of this actually happening? Has anyone studied this phenomenon? If so, how is this possible?

I heard about several incidents involving dogs finding their way home. Here is one news article:

I think there was a movie or two about such dogs, too. Maybe they were fiction.

The Master speaks: Can dogs and cats really find their way home over long distances, as in “Incredible Journey”?