According to Google Maps, it's 665 miles or 10 hours and 5 minutes.
http://maps.google.com/maps?f=d&hl=en&geocode=&saddr=sault+ste.+marie,+mi&daddr=elizabeth,+in&sll=37.0625,-95.677068&sspn=33.710275,76.992187&ie=UTF8&z=5
