Complex sentence: The drive continues for 20 miles north on U.S. Route 160/U.S. Route 491 to Cortez, the county seat of Montezuma County.
Split into simpler sentences: The drive continues for 20 miles north on U.S. Route 160/U.S. Route 491. The route continues along U.S. Route 160/491 to Cortez, the county seat of Montezuma County.