BTTM Census Search: Mary Jane Savage (1860-1957)

Need to determine her married name.

Cannot find her as Savage on any Census. Need to do detailed search from home on the following:

1860 US Census: Cannot locate her parents.
1870 US Census: Family found, she's not listed (age 10).
1880 US Census: Cannot locate her as Savage.
1900 US Census: Cannot locate her as Savage.
1910 US Census: Cannot locate her as Savage.
1920 US Census: Cannot locate her as Savage.
1930 US Census: Cannot locate her as Savage.

Born in Salt Lake City, UT.

Obituary? -- she lived to be 97 years old.

Note: She has a twin(?) sister named Sarah Jane Savage -- could this be the same person, instead of twins?

1910 US Census Search: Christian Olson Midtvoldseiet

Probably in North Dakota, widower

Have not found him living with any of his children. Try grandchildren? Siblings?