The Porcupine Mts. are a great place. We had a group of scouts backpack there three years ago, the week after Easter. (They have been doing the Appalachian Mts. the last two years.) The water was high from the snow run off, and they got some wet feet.
I use to take a group of first year scouts every other summer to the Porkies. We would rent the 8 man cabins, and backpack from one cabin to the next for 3 or 4 days (Watch out for the leaches in Mirror Lake!) Also, we stopped at Picture Rock National Lakeshore and at Sylvania Recreation Area, each for a night on the way up.
On the way home, we took the ferry across Lake Michigan from Wisconsin to Ludington, Michigan. I guess the reason I stop taking this trip was that I like Ontario better, it is not as crowded, and I do not have to worry about booking cabins a year ahead. If you plan on camping in the campsites along the trail in the Porkies, they fill up fast in the late summer (when the bugs are not so bad). Isle Royal is the same way. You better make camp by 2:00, or you might not get a place.
-----------------
The trips north of the Sault are special summer trips, lasting 6 to 8 days. The group size to go into the interior at Lake Superior Provincial Park is 9, and at Pukaskwa, it is 8. The last two summers, we had two groups up the same week in August doing different itinerary. (Again, the bugs are not bad this time of the year!)
This last summer, I charge $125 for a canoeing trip down the Sand River - 8 days; and $110 for the 1st yr. scout trip - 6 days. Each group took the Agawa Train into Sand Lake, the 2nd group took the train out the next day. I own the canoes, canoe trailer, etc. so we do not have to rent.
The trips to the Bruce Peninsula and Hocking Hills are usually every other year, 3 day trips. I had 50 people at the trip to Hocking Hills last April. We do the Bruce Peninsula trip Memorial weekend.
I have never been to North Manitou Island, but have been to the South Island two times. Every June, I backpack one or more scout groups into the Nordhouse Sand Dunes on Lake Michigan (south of the Sleeping Bear) for one night. I believe it is the only Federal Wilderness Area in the lower part of Michigan.