We may not have a connection, but I am also researching my great-grandmother's maiden name which is Sanderlin. Her name was Clarinda Sanderlin and She married John Jefferson Grogan. You can read my mail that is Clarinda Sanderlin Georgia which is just below this message. I know you are researching someone in Texas, but I have also located a "lost' Grogan cousin in the Dallas, Texas area. Like I said, there may not be a family connection, but I had to mention this to you since a Grogan married a Sanderlin. Also, my great-great grandparents name were John and Mary Ruddell Sanderlin and they are buried in Cherokee County, Georgia which is not too far from Atlanta, Georgia.
I do hope that you get a lead from this. I have information on the Grogan family back to the 1700's when they came to American from Ireland, but I can not locate anything on the Sanderlin family.