There was at least one work (POW) camp in Door County, WI (NE WI) during the war. The Door County Advocate has had stories on them. You may try them: www.doorcountyadvocate.com or the Door County Library or the Peninsula Genealogical Society or the Door County Historical Society (Orville Schopf). Some of them were involved in picking cherries & working on the farms. Someone told me that some of them who had abackground as a stonemason worked on cutting limestone & building homes.