[2] She rode 14 miles (23 km) and preached every evening and three times on Sunday, until the end of the meeting, then continued his work for two months, until he recovered his health.

[4] She was also active in mission work, serving as secretary of the Illinois Conference's Woman's Foreign Missionary Society of the Methodist Episcopal Church for four years.

In 1883, she was elected delegate to the Right Worthy Grand Lodge (RWGL) of the World, held at Washington, D.C. At this time, she entered the national work of the IOGT, under the Eastern Lecture Bureau, speaking for 39 summer assemblies, including those of Canada, New York, and Pennsylvania; and she returned to these encampments five years in succession.

She lectured in 127 towns in that State, organized 87 Unions, children's temperance societies, and 10 White Cross bands, and, with her husband, aided in the conversion of over 4.000 persons who united with various churches.

She also campaigned for Prohibition in Illinois, Washington, Idaho, Montana, Colorado, California, Wyoming, South Dakota, and Ohio.

[2] During World War I, she served as camp mother in the Base Hospital at Fort Riley, Kansas, under appointment of the State WCTU.

[2] When over 60 years of age, St. John took up a homestead of 320 acres (130 ha) in Colorado, and without assistance, improved the land, and proved up on her claim, which she later sold at a profit.

[2] On October 7, 1920, in Salina, Kansas, St. John married Francis Worcester Mann (1845–1931),[5] of Devils Lake, North Dakota, who had been a childhood friend of hers in Illinois, and with him settled at Long Beach, California.