Complex sentence: It crossed the Straits of Mackinac and then used U.S. Route 23 and old U.S. Route 10 to Detroit, old U.S. Route 25 to Cincinnati, current U.S. Route 25 and U.S. Route 25W to Knoxville, and U.S. Route 70 and U.S. Route 27 to Chattanooga.
Split into simpler sentences: It crossed the Straits of Mackinac and then used U.S. Route 23 and old U.S. Route 10 to Detroit. In Ohio it is old U.S. Route 25 to Cincinnati, current U.S. Route 25 and U.S. Route 25W to Knoxville, and U.S. Route 70 and U.S. Route 27 to Chattanooga.