Your mother donated a number of documents to the historical society in 1980 which were key to my discovery of my wife's paternal great-grandfather.
Sandra's mother was Luverna Johnson (29 Dec 1902-3 Feb 1968). Luverna's father was Christian Rasmus Johnson, born ca 1842 in Denmark. Christian was your common ancestor with my wife. Luverna's mother's last name appears to be Severson, though that's about all I know of her. She was Christian's second wife. My wife's family is descended from his first wife. My father in-law and his siblings knew little more about him than his first name, that he had two sons, Albert and Bernard and 2 or 3 girls from his first marriage and that a Mrs. Longcor came from the second family. My wife is descended from Bernard.
Christian's brother Lewis maintained a diary for several decades and settled a mile away from Lewis in Goodhue Township, Goodhue County, Minnesota. The diary was included in the material donated by your mother and gives an interesting account of life in early rural Goodhue County.
The donated material also includes Christian's discharge from the union army and his Danish passport, along with an older hand-written sheet of family information in Danish. Picking out names from that document, it appears that Christian's name was originally Rasmus Christian Jorgensen. I've been able to find Danish records for him that correspond to the names in the hand-written sheet. His parents apparently were Jorgen Larsen and Catrine Hansdr. Jorgen's parents appear to be Lars Nielsen Buch and Karen Sophia Olsen. All are from Utterslev, Maribo, Denmark.
It further appears that Jorgen Larsen took the name John Larson when he emigrated with his sons to America. Catrine took the name Katrina. They are both shown in the 1880 census living in Red Wing with birthdates that correspond with the Danish record. The material your mother donated also included a deed to John Larsen, which on the surface seems out of place until you realize this connection.
Thanks again to your mother for her donation of material that has been very significant to my discoveries.