You might want to try the Northern Great Lakes Visitor Center in Ashland, WI. It handles quite a few counties in northern Wisconsin. I have searched there for my boy friends Polish ancestors there. The address is Northern Great Lakes Visitor Center 29270 County Hwy. G Ashland, WI 54806. Their email is: email@example.com
I noticed that Mary died on 15 Feb 1968. Her maiden name is listed as Greziak on Lucille's death record.