I don't know if you are still in need of this information but if so, then yes, I have information on the Kafers in Iowa. First, the last name also appears on different documents as "Keefer" or "Kaifer".
Christian Kafer is my great-great-great grandfather (through his son Jacob Kafer, b.1834). Christian also had a son "W. Mathias Kafer", b.1839. "W. Mathias Kafer" married Mary A. Hense, and had a daughter Laura Salone Kafer, b.1870. She is probably your Laura.
W. Mathias was from Wurttenberg, Germany and arrived in this country on June 15, 1859 on the William Tell. This ship departed from Le Havre, France and came into NY. W. Mathias Kafer is buried in Lafayette, Iowa, which happens to be about 3 miles from Alburnett Iowa where I grew up. The family members coming over on the ship were: Christian Kafer & A. Maria Kafer, and their children Anna, Maria, Christian and Catherine. (There last name was spelled Kaefer on the ship passenger list.).
Let me know if there is other information I might have that you need.LorieNYC@aol.com