Carol...I printed a mapquest from Split Rock lighthouse to Ontonagon, MI and from Ontonagon to Houghton. I stopped it at Ontonagon because I thought that we would try to stop at the lighthouse there before continuing to Houghton.

This is the mapquest results:
Split Rock to Ontonagon---216.77 miles, 4 hours, 40 minutes

Ontonagon to Houghton---51.52 miles, 1 hour, 13 minutes

Total miles: 268.29
Total time: 5 hours, 53 minutes