It would be interesting to track her before being a nurse in the Frankfort, KY hospital.
The FamilySearch profile for her has a LNAB of Cummins. In the Notes Section a comment said that came from the 1925 Iowa Census of daughter Nettie. I looked at the 1925 Iowa Census image. No where on the page is there a place for parents' LNAB. I question the accuracy of the comment in support of Cummins.
One of the sources in Mary's FamilySearch profile is that she is mentioned in the 1889 marriage record of daughter Almedia. The record lists the mother's maiden name as Semmons, (No image attached, so I could not verify that). That could be a spelling variation for Simmons.
Assuming the 1870 Census record added to her profile is correct (I think it looks to be the right record for her - family names match). There are no children from her first marriage in the household. Likely recently married when husband Roberts entered the War.
What brought her to Frankfort, KY? If she was from Ohio and wanted to assist in the War effort, there were several locations within the state of Ohio. Cincinnati had a large hospital. Camp Chase had a hospital. Just to mention a couple. So, why leave the state? Did she and Roberts move to KY? Or, is that where her 1st husband died? Could check Ohio regiments deaths for a someone named Roberts who died at Frankfort.
(Now that the Source-a-Thon is over, I can catch up on all I missed).