You can get the surprise of your life when you use an online-mapping service such as Google Maps or Mapquest.

When I punched start and end points into Google Maps for a trip last week near Yosemite, the suggested route included a Jeep trail that was built in 1916-17 to 1913 wagon-trail standards, has been closed to traffic since 1938, and now sits in designated wilderness open only to hikers and horses.