SW,
i can relate to the ISLE ROYAL QUEEN comment.
my first trip to isle royale was on her because i live in mi.
i remember hearing stories about the rough water on the lake going to the island.
when we pulled out of Copper harbor i was expecting the worst but it turned out to be the BEST boat ride i ever took!!!
the lake was  smooth as glass and the sun was out!!
we sat on the deck the whole trip and watched two small outboard boats, under 20 ft  follow in our wake all the way over.
the Capt said it was only the second time in all his years he ever saw lake that calm.
after trip we flew back from rock harbor and i'm glad we did because the lake was tossing and turning like you would expect.
For those going out of mich, i would seriously consider flying out of Copper harbor if the seaplane service is still running??
we did the next two trips and were glad we did.
it's so much faster,the view is gorgeous and they can haul canoe's or kayaks.
 all 3 trips we took a week to do each of the 3 trails.
since there was 4 of us and one had bum knee, i think we went at fairly easy pace.
as for portaging with a canoe, i still think if you packed light and shuttled the worst parts of trails it wouldn't be that bad?
you would want to be in GOOD shape but that's a given on trip like that!
i know those 3 trips were just about the best experience i ever had backpacking!!
there's been talk about the island losing it's national park status due to low attendance and high operating cost's??
i hope that NEVER happens but you never know these day's??
one of the local papers a few years back ran a story about a private developer who was negoitating with the goverment to buy island and turn into luxury condo's and boat livery's??
i hope that was just speculation but money talks and it could very well happen :'( :'(