I need records to find Lars Anton Anderson

Can you help me find records concerning my greatgrandfather: Lars Anton Anderson? On his tombstone it states he was born in 1831 in Norway, and died in Nebraska 1908, but the court house does not have a death certificate. He married Osty Hansen in Norway and emmigrated to the US in 1860 and she born 1836, died in Nebraska in 1907. I have their ship trunk that says "Manhattan Kansas Nord. Amerika" on it. So they made to Kansas, later Clay Center, Kansas and then Hyannis, Nebraska. I know they had a son Lewis Anderson (my grandfathter)b. 9/27/1873 in Clay Center, KS.