My wife and I rode a 900 mile loop around Michigan in 2012. A portion of our route took us over some of the same ground that you may be covering. We started south of Detroit and the apex of the loop was Mackinaw City. We did spend a day on the Island.
Roscommon to Mackinaw City is a little over 100 miles. Using Google Map bicycle routing feature, it would route you up through Gaylord. We approached Gaylord from the east, so we did not ride the first portion of your potential route. However, my wife kept a detailed journal that includes route details. If you are interested, I'll send you the details. I believe that most of the route from Gaylord to Mackinaw City, 62 miles, was on Rail to Trail paths. Most of this was not paved, but it was pretty easy riding.
You can check this out at:
Just a quick look at the various Voyageur models leads me to believe that the bike would do fine as long as the load carried was not excessive. Depending on your conditioning, the ride could be done in 2 or 3 days.
Although I left Michigan after finishing school, I found that after all this time it is still a wonderful place to ride. If you have not been to Indian River, the Cross in the Woods is worth the short side trip.
PS. I need to warn you that travelling by bike is addictive
Last edited by Doug64; 01-13-14 at 12:35 AM.