We were on a drive through the Keewenaw with a local map looking for something to do when we stumbled on an old mine. well, we knew where it was, but we hadn't planned to go there. Although we had trespassed to get some pictures (I DON'T recommend this - it's dangerous and illegal) many of the mines can be seen from the roads and a couple are open for tours.
A good local map may even show some ghost towns. If not, and you have a good memory (or GPS!) you can wander around on some side roads and possibly spot some old abandoned towns. We found one with a few remaining houses in it. The people left without taking any extras. Whatever fit in their wagons was all they took. It really is like stepping back in time. Be advised that they don't look like the western ones you see on TV. these are not that glamorous, but they offer a glimpse of what the miners of the 1800's lived in. It's been about 13 years (as of this writing) since I have visited the ghost town we were in, so it may have deteriorated beyond recognition. But, according to our map, the peninsula is scattered with them.