I am a granddaughter of Selmer Neal Martin Johnson and we lived on the dairy west of Plentywood while my siblings and I were growing up. Grandpa had Parkinson's and my memories of him were in a wheel chair and being cared for by his wife and my grandmother, Alice Livdahl Johnson. Both of my grandparents are buried in the old Plentywood Cemetery, Harry and Myrtle, Kermit and Roy also.
There is an extensive family history under the Daniel Johnson family name. Selmer and Alice had six children...Kermit, Harry, Myrtle, Roy, Stanley and Alma. Harry and Myrtle died young, but the other lived a full life and Uncle Stanley still is alive and living in Portland Oregon.
I don't think the Daniel and Sarah lived in Plentywood...unless it was to homestead and then went back to Iowa.
I live in Flaxton North Dakota now and a hundres miles to the East of Plentywood. Ironically, grandpa Johnson has lots of family in this area...Lignite, Flaxton, Bowbells. It would be fun to visit with you. firstname.lastname@example.org