I believe I can help you. Joseph Blackford Crubaugh (1840-1925) married Martha Jane Elliott (1839-1974) during 1865. They had three children: Abram (1867-1869), David (1869-1872) and Joseph (1873-1895).These are almost certainly the "step-brothers" that you mentioned. After Martha's death, Joseph remarried and had fathered three more children: Oliver, Clarence and James. I actually met a son of this James in the 1970's. I believe that Dawson Elliott was probably Martha Janes's brother and therefore your gg-grandmother would have been a first cousin of the David and Joe Crubaugh brothers.