North of Spokane near Kettle Falls, the Kettle Crest / Sherman Trail loop (17 mi. / 2,500ft) combines horseback riding trails with forest roads. Starting from Sherman Pass on SR20 west of Colville, ride north on the KCT(#13) over Jungle Hill. Head west on the Sherman Trail (#12) to FS65. Follow FS65 southwest to SR20 and climb east back to the parking area.
To reach the horseback riding trailhead from Kettle Falls travel U.S. Highway 395 to state Route 20. Follow state Route 20 for 25 miles to Sherman Pass. Turn right on the trailhead access road.
The KCT does continue on past the ST and can be a nice extended trek.
Overall, Kettle Crest / Sherman Trail is the 19th most popular horse trail of all 32 horseback rides in Washington.