I was stuck on a certain relative who apparently left the area where she grew up sometime after she was enumerated in the 1910 census in Hancock County, Illinois. She seemed to evaporate and appears in no later records.
In 1915, in the church she attended as a child, she and her husband have two of their children baptized. The baptism records list the maiden name of the mother. While I’m not yet 100% certain it is her, it’s a very good lead. One child has her maiden name as it’s middle name and the other child has her mother’s maiden name as it’s middle name–another good clue.
Did you relatives bring the kids “back home” to be baptized?