Complex sentence: The Barlow Road (at inception, Mount Hood Road) was the last overland segment of the Oregon Trail, crossing the Oregon Cascade Range before reaching the Willamette Valley.
Split into simpler sentences: The Barlow Road (at inception, Mount Hood Road) is a historic road in what is now the U.S. state of Oregon. It was the last overland segment of the Oregon Trail, crossing the Cascade Range before reaching the Willamette Valley.