Her 1916 Michigan death certificate shows her parents as J. Burgess and Mrs Srackengast (see Seeking Michigan under the name Martha Griffin).
I suggest trying to find an obituary for William. It probably won't have his parents but it might list surviving siblings. Check a local library or historical society. Knowing what church he belonged to might help too. Sometimes the death certificate or marriage record for a son or daughter will list exactly where the parents were born. It's a long shot but it sometimes pays off .