Olaf Frederick Olsen: Looking for info about

I am looking for information about the heritage of Olaf Frederick Olsen, born in May of 1850 in Tonsberg, and died 7/12/38 in Minneapolis, MN. Wife Anna Marie Lampe (married 5/5/1872, Tonsberg). Eight children: Olaf Frederick Jr, (b 1873), Axel (b.1876), Hildegard (b.1877), Signa Charlotte (b.1879), Maria (b.1882), Harold (b.1884), Mattie (b.1886), Ralph (b.1890). In Minneapolis, he started the Olsen Fish Company. I do not know when he came to the US, probably between 1886-1890 as his last child was born in MN. Family story has it that Olaf was a wealthy man in Tonsberg, having three businesses:a lumberyard, a big ship, and a boys school. But the lumberyard burned, and the ship sank, and the school also failed. So Olav came to the US alone to work at a lumber camp in Iowa, as a timekeeper (?). In 1886, his wife Anna Marie auctioned off all the family belongings in Tonsberg ("big house on a hill with French wallpaper, grand piano..") and came to the US via Boston, taking a train to Minneapolis. He didn't know she was coming. (They had friends named Rasmussen in Minneapolis; she stayed with them.) She sent for him, he came. Next week I am traveling to Norway and visiting Tonsberg. I would like to know anything about Olaf's or Anna Marie's ancestry. Thanks for any help.