I think it is likely that your William in Iowa is the son of Adam and Margaret Dillman Klinefelter.This is a sentence from "The Evangelical Church in Ohio," by Roy B. Leedy (The Ohio Conference of the Evangelical United Brethren Church, 1959) pg. 732, "A son of Adam Klinefelter, William, was a minster in the Des Moines Conference and a daughter Kate Klinefelter was the wife of Rev. H. J. Bowman."
I also know that Adam's daughter, Elizabeth Klinefelter Long moved to Mason City, IA with her husband and children.
Please contact me if you would like to exchange additional information.