Considered the crown jewel of the nation's rails-to-trails initiative, the Route of the Hiawatha winds through the rugged Bitterroot Mountains in the St. Joe Ranger District of the Idaho Panhandle National Forest along an abandoned section of the Milwaukee Railroad. Its gentle 1.6-percent to 2-percent, all-downhill trail straddles the Idaho-Montana state line for 15 miles, delving 10 dark tunnels and crossing seven sky-high steel train trestles.