Looking for David Tullucksen Moe

David Tullucksen Moe came to Boston, MA from Norway about 1893 with his wife, Carina Pedersen and 2 sons, John & Walter Moe. David left his family in Boston area and went to visit a brother in WA and died there in 1928. I haven't the slightest idea how to go about finding where the family came from in Norway and who the brother was in WA. The family has always said that Moe comes from the Valley of Mo in Norway.