Getting to Isle Royale
Your choices:
Ranger III - Houghton to Rock Harbor
Owned by the Park Service.
Isle Royale Queen III - Copper Harbor to Rock Harbor
Shorter ride than the Ranger III but you have to drive further north to catch this boat.
Seaplane Service - Houghton to Rock Harbor and Windigo
This is obviously for those that can't wait to get there. It is the fastest (and most expensive).
Wenonah & Voyager II - Grand Portage to Windigo
If you're coming from Minnesota, this is your choice. The Ranger II will also stop and pick you up at various stops around the island which means you wouldn't have to plan a circular hike.