This is a great data mining project from Randy Olson who was inspired by Discovery News to plot out the optimal road trip path through every one of the 48 contiguous states.
With 50 landmarks to put in order, we would have to exhaustively evaluate 3 x 10^64
possible routes to find the shortest one.
That's a monumental task for a person, but not quite so big for a computer. So that's where Randy used Google Maps API and machine learning to plot out the map. But he didn't just make one map. He made several, and not just for the United States either (London, Canada, France, and Germany are included too!).
You can visit all 47 National Parks with almost no backtracking (efficient!!!), you can simply step foot in 48 states by visiting 50 major US landmarks, you can even skip the boring parts and go straight for popular destinations in all 48 states!
And if you don't drive, there are walking tours too for NYC and Philadelphia!