Complex sentence: The John Wayne Pioneer Trail follows the former roadbed of the Chicago, Milwaukee, St. Paul and Pacific Railroad for 300 miles across two-thirds of Washington from the western slopes of the Cascade Mountains to the Idaho border.
Split into simpler sentences: The John Wayne Pioneer Trail follows the former roadbed of the Chicago, Milwaukee, St. Paul and Pacific Railroad across two-thirds of Washington. It passes from the western slopes of the Cascade Mountains to the Idaho border.