I know this is an old post, but I'll take a chance. My gr-gr-grandmother was Mary Lange, married to Christ Rohrbeck in Kankakee Illin 1864. I found what I think is her brother Wilhelm Lange, who lived in Will County, Illinois, them moved to Remsen, Plymouth County, Iowa. Mary and Christ had seven children, most in Will County Ill, then moved to Carroll County Iowa. They were all in 1880 census, then parents no longer to be found in Iowa 1885 census,but children were separated and still living in the area.
I also have Berger family in my tree. A Berger from Jefferson, Jefferson Co. WI married an Eiden. My gr-gr grandmother was Anna Eiden, from Jefferson WI, who married a Conrad (or Konrad) Daniel, and they lived in Beaver Dam. ( I think the Berger married to Eiden was one of Anna's brothers). One of Anna's daughters married my gr- grandfather Adam Schleisman who was from Lidderdale, Carroll Co. Iowa. This also happens to be where the Rohrbeck children ended up living after the parents were gone. I'd be happy to share what I can with you. Hopefully by now you have added to your information.