Complex sentence: Before European settlers came to the UP, the route of what would become US 2 was used as part of two Indian trails, and the Michigan segments of the Theodore Roosevelt International Highway and the King's International Highway auto trails.
Split into simpler sentences: Before European settlers came to the UP, the route of what would become US 2 was used as part of two Indian trails. It was also used as a part of the Michigan segments of the Theodore Roosevelt International Highway and the King's International Highway auto trails.