In the 1900 census, the family surname is shown as Kingman rather than King...? Also, there is a son, Darrell, born July 1898.

A school was built in Dallas Center about 1875. You can read about it on the Dallas County Genweb site: http://iagenweb.org/dallas/twp/adel/dallascenterhistory.htm Children living in town would have undoubtedly gone to that school. It probably has morphed into whatever school is there today -- probably a portion of a consolidated district -- but is doubtful that records for elementery-age children exist; at most, there would be yearbooks detailing the graduating class members.

For library work, I would recommend the Dallas County Genealogical society. Their fees are *very* reasonable and they have created most of the indexes and collections for the area. http://www.rootsweb.com/~iadcgs/