I hear you.  We frequent the keweenah Penisula during the summer since we have family up there.  I would definitely be in for a 50 if not a 100 in the UP.  To me, it is the most remote place in the midwest, and with roads that run for miles along lake superior, you could probably plan a 50 that runs 80% along the lake.  The only negative is that you want to jump in...

I am running a 25k trail race up there this summer. "Run the Keweenaw" I have never been up to Copper Harbor so I thought this was a good reason to head way up there. http://www.runthekeweenaw.com/