That's what most folk think Wally. Isle Royale is very much a paddlers park too. With water taxis to shuttle you and your boat around a variety of trips can be had. We are planning between 10 and 13 days this june with the canoes. Here is a forum where you might find some info.
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Jim DuFresne has an excellent book on Isle Royale which includes both hiking and paddling aspects of the park. Ferry costs are certainly offset by the inexpensive backcountry fees of $4 per night.