In the 1880 census living with Margaret RHODES CROCKER is her nephew, Eugene CROUCH, age 20, b WI (should be IL). Eugene's parents were William Thomas CROUCH and Mary E. CHRISSMAN.
In the 1850 census Mary E. CHRISSMAN was living with her parents in Akron, Summit Co., OH. In 1860 Mary was married to Wm. and living in Durand, Winnebago, IL with son, Eugene, age 1, b IL. The CROUCH family (along with Mary's parents) were in Ca by 1870.
As Margaret RHODES CROCKER was born ca 1822 in Summit/Stark Co., OH, the same area where the CHRISSMANs were living in 1850 I'm thinking that the family connection is through that line.