Found their passenger list:They departed Liverpool 9 Mar 1904 on the Ivernia and arrived Boston 7 Apr 1904, listed as:
Kristian Vilhelm Nielsen 24, Maren Nielsen 23, Hans Peter Nielsen 10 months, from Tornby Denmark
Their destination was "brother Niels Peder Nielsen, RFD No. 4, Spokane Wash"
This would be the older brother listed in the 1880 Danish census, born 17 Jun 1872 Vrejlev, and here is his registration for immigration at age 16:
Name:Nielsen, Niels Peter Occupation:Tyende (m/k land) Age:16 Destination:New York Contract no.:343700 Registration date:4/15/1888 Last res. parish:Vrejlev Last res. county:Hjørring Last residence:Vreilev, Hjørring Destination country:USA Destination city:New York City Destination state:New York State
He is listed in the 1910-1920 Spokane County censuses with a Norwegian-born wife Augusta and children Anna, Gena,John, Ella, Pearl, and Alice.
Washington deaths lists a Niels Peter Nielsen who died in Spokane 10 Mar 1946, age 73.