My grandmother's family was kin to the Coffelts. Her cousins, Robert and Sue Coffelt, have written a book on the Coffelts. They live at Meridian (Bosque County) TX. Another relative, Rex Coffelt, a surveyor, lives at Walnut Springs or Iredell, also in Bosque County. Johnson County is adjacent to Bosque County. I'd be willing to bet they are related to your Coffelts.