I assume norther MN, WI and MI are like Northern Ontario. If so, their only real main conservative issue is guns.
Not really. The U.S. political dynamic is a little different.
There are plenty of socially liberal rural areas. The ones you mentioned are some of the few areas where entire counties encompass them, though.
I have no idea what part of rural Iowa would be considered socially liberal.
But just because an area is populist and union doesn't mean it isn't also socially liberal. There's a copper mining town in the Cascade Mountains that votes heavily for gay rights, drug legalization and abortion rights whenever those issues come up.
There are alot of rural parts of Upstate New York that are pretty soically liberal too. Also parts of the Rockies are pretty liberal too going with the tradition in the area of keeping the goverment out of people's lives.