Just yesterday I received the marriage record from New York State that gave me the needed information. Mary Ann's name on the marriage record is Marian Lightowler. William and Mary Ann were married May 12, 1898 in Mount Vernon, New York by Reverend George Clarke Peck. Reverend Peck was the pastor of the First M.E. Church in Mount Vernon.
According to the marriage record, Mary Ann (Marian) was living in Mount Vernon at the time while William was living in South Salem, New York. I still have not established how they knew one another. More research to be done! Stay tuned.