Is there a website (and if there isn’t, there should be) where you can put in a starting place and a destination, and besides showing the best route to get there (as Google and Mapquest do), also show special sites and features that are along the way, and how far they are from the main road?
I would be terribly upset if I were to take a road trip and find out I missed and passed within a couple of miles of Buck & Jaspers Tumbleweed Farm or the Worlds Largest Clothes Drier Lint Ball.
If you join either AAA or Good Sam Club (cheaper, at $15/year), you can get travel guides for whatever route you are planning to take.
http://www.roadsideamerica.com/map
It has the points on google map, I’m not sure if there is a way to add directions to it.
If you enable Panoramio and such layers in Google Earth you will see the many dots of photos people took. Any interesting place will have lots of them.
Most any automotive GPS unit will do that. You choose categories of POI and it will alert you when you get near them and direct you to them at the touch of the screen. Some of them have up to 8 million POI.
If you prefer planning rather than spur of the moment you can also preview your trip and include those you choose in your route.