Seeking Tennison Immigrants

I am researching the Tennison family of Wisconsin and later North Dakota. I have been looking for a Michael Tennison, born around 1818, wife Bertha, and children Mary, Tennes, Peter and Martha. They are in the 1860--1880 censuses for Marquette County Wisconsin. But I can't find them in a 1850 census, so thought maybe they immigrated after 1850. I don't know Michael's fathers name or the farm name. In looking through passenger lists for a Mikkel I found a listing on the ship Emigrant which sailed in 1852 for a Mikkel Drange, wife Bertha, and 9 month daughter. If Drange is the farm name where would I start looking for records of them?