Rasmus Thompson

Hello, Im hoping someone can direct me in a good direction. Im helping my Wife Debbie Thompson with her Genealogy. Her Grandfather was Roy Thompson. The only link above him is his Dad Rasmus Thompson born about 1865 in Norway. I see him in 1910 US census. Married to Caroline J Thompson. Came into Oakland San Francisco area. late 1890 ? Ive done a search but am asking for help above Rasmus. From Norway possible name changes even slightly? Thomson? Any help is appreciated. Rasmus died in 1916 Oakland . Regards Dave