Marshall graduated from Wheaton College in 1965 with a BA in French while studying modern dance at the New England Conservatory. The following year she studied Japanese classical dance in Kyoto, returning to New York to work at the Japanese Consulate and study Japanese at the New School. In 1966 she married her first husband, Timothy Buxton, and they moved to Stanford University, where she worked at the International Students Center. She then earned an MA in French from Columbia University Teachers College, and taught French the next year at a public junior high school in Exeter, NH. In 1970 the couple led a group of college students to Ghana, West Africa for Operation Crossroads Africa, a program that JFK called "the progenitor of the Peace Corps." Her husband died there at age 28 of a fever.