Hello, In regards to what PA means on a census record: It means that the person filed PApers to start the naturalization process. I don't know if he finished the process or not. There are three steps to become naturalized. 1)Declaration of Intention--which is probably the PA mentioned in the census 2) Petition for Naturalization 3) Oath of Allegiance
Depending on when he started these papers will determine how much useful information you will find.
You could write to the Columbia Co. Courthouse and get a copy of that paper, or a Historical Society near Portage.
My grandmother was a Klish/Klysz. Other variants were Klies, Kleish. She was born in the Town of De Pere, Brown Co. Wi. in 1883, parents were Frank Klies and Josephine Jakubowsky. Maybe we will find a connection someday? There are other Klish families in Portage Co., around the Steven's Point area. I believe they might be related to me, but did not find a connection yet.