I don't know if there's transport to the various ferry docks, but if his parents wanted to travel a bit, they could fly to his previous destination, rent a car, pick him up, and drive up to Houghton or Copper Harbor (as my son put it, "drive to the end of the world, turn left, go another 50 miles, and get on a boat.") It's pretty country, and could make a great vacation for them, too.

Absent that, transportation could be an issue. (Of course, if he could get to Dayton, Ohio, mid-summer, I could always tell my wife, "But, honey, he has no way to get there, so I guess there's no choice but to take him and then go over to the Isle with him. It's rough duty, but someone has to help these kids...")