Mary Alice traveled with her mother, Elizabeth Hall Mills, and sister, Martha. Her father, John Mills, and oldest sister, Elizabeth Mills, traveled with the David Wilkin Company in 1853. The two companies traveled closely together. It is uncertain why the family split between two companies.
Her death certificate shows her name as "Mary Alice Collier." It confirms her death date, but shows her birth date as 22 September 1837. This birth date may be in error because the inscription on her gravestone in Idaho shows her birth year as 1842.