Although it's the only guide written for Michigan's largest state Park, it gives you everything you need.
DuFresne knows Michigan and thoroughly covers the Porkies. The guide is detailed and informative with topo maps of all the trails as well as access points, difficulty, hiking time and mileage break-downs along every trail. Though geared towards hikers and backpackers, it also covers winter activities and fishing.
I really like how he breaks down all the trails extensively and also gives you plenty of options depending on what length of a trek you're looking for-from a day hike up to a 6-day excursion.
This is the 3rd book of his I've bought and I'd buy anything the guy has to sell- great book.