Sully shares with Dr. Quinn his family background. His father died before Sully could remember him. His mother drowned in the Hudson River when he was ten years old. He left New York City at that time and moved to Colorado. Sully does not mention his brother. His brother is the reason Sully was afraid of riding horses.
During the arrival at Beacon Hill, Colleen tells the girls during tea, that the streets in Colorado Springs are all dirt, not the cobblestones as corrected by one of the girls (when Colleen referred to the Boston streets as rocks) when in fact, several roads scenes around Boston in several scenes are dirt or dried mud.
In the pilot of Dr. Quinn, Medicine Woman, Michaela reads a letter from her mother that says Mary is pregnant. Michaela tells the children that Mary is her sister. The names of Michaela's sisters are Rebecca, Marjorie, Maureen, and Claudette.