Have you checked out the DNR website? Easiest way to find what you're looking for is to start out by Googling a park, such as Brighton or Highland, and then perusing their hiking link. You might find some hiking only trails in the same parks as some of the more popular and challenging mountain bike trails, or you may at least find something in those areas. Of course, it only covers state-owned land. Unfortunately, you're not going to find anything that comes even close to what's in the Keweenaw, but, IMO, you're in one of the best areas in the Lower Peninsula.