Nelson/Vigen/Flakne

I am researching the above names. My gggrandfather was Nils Olson born Dec. 1808 in Vermeland, Sweden and married Christine?? born Dec. 1814 in Vermeland. They had Nils Nelson born about 1850 and Gustav Nilsen Vigen born May 9, 1852. Nils Nelson is my great grandfather. He married Christine and they had Kristine, my grandmother March 17, 1887 in Bergen. She married John Flakne and lived in Plentywood, Montana until her death April 5, 1941. In her obit, it is stated she immigrated in 1905 but I cannot find her with the age given. Nothing is listed as far a siblings, etc. I am trying to locate any records for her in Norway. She supposedly immigrated to Adams, Walsh County, North Dakota. Any help would be greatly appreciated.