|Mary Elizabeth Hildinger Johnston|
By 1914 they were living in Trenton, New Jersey where David went to work for Mary's brother Charles in the movie theater business as a manager of one of his theaters. In the 1910 census his occupation was listed as Foreman, Dept. Stables.
Their daughter Luella was an accomplished musician and organist and apparently this may have been inherited from her Johnston side. In notes from Mary Aleta Winslow, http://www.pagenweb.org/~elk/winslowgenealogy/mywinslowburkeancestors.htm Eliza Mariah was supposedly from a musically gifted family.
Mary Elizabeth and David Johnston lived in Trenton until at least 1943, but I have been unable to find any record of their deaths despite numerous searches.