Bob, there are plenty of cache's in every state, and Michigan is no exception. Remember Von Mueller's admonition, "There are probably several within walking distance of where you live, if there were just a magical way of finding them."
You can research old newspaper files, and get your leads from there, if you want. It just depends on where your interest lies. Bob, some of us are turned on by hidden monies left from crime, of that of an old recluse, miser, farmer, businessman or woman, banker, lawyer, lumber baron, shadetree mechanic, lifelong bachelor, divorced and bitter person, crooked cop, moonshiner, et alia. Follow your interests, Bob, and do what works for you.
Remember luck is preparedness meeting opportunity.
There is plenty where you live.
Good luck!
Exanimo!
The Gringo