Gunild Nilsdatterr Kleven under Askilt

Gunild was born 1790. She is the mother of Halvor Johannesen who sailed to America in 1855 with his wife Rannei Thordat and family. There is no mention of Halvor's mother making the trip to America with her son Halvor in 1855 ....yet there is a 70 year old Cornelia Kleven that shows up on the USA Census of 1860 living with Halvor's family. I'm looking for any information on Gunild leaving Norway as a 60 year old.....there is also some information about a Andrew Kleven (Cleven) in the USA census of 1860 as a 17 year old living with the Halvor Johannesen (Johnson) family that we think might be related but have no information on.