In late 1959, Perlman and his wife took a cross-country motor scooter trip, mostly on two-lane highways traveling at 25 miles per hour. From 1959 to 1963, they lived on the lower east side of Manhattan while Perlman worked on a statistical analysis of the world's resources with John Ricklefs. They participated in anti-bomb and pacifist activities with the Living Theatre and others. Perlman was arrested after a sit-down in Times Square in the fall of 1961. He became the printer for the Living Theatre and during that time wrote The New Freedom, Corporate Capitalism and a play, Plunder, which he published himself.

In 1963, the husband and wife left the U.S. and moved to Belgrade, Yugoslavia after living some months in Copenhagen and Paris. Perlman received a master's degree in economics and a PhD at the University of Belgrade's Law School; his dissertation was titled "Conditions for the Development of a Backward Region," which created an outrage among some members of the faculty. During his last year in Yugoslavia, he was a member of the Planning Institute for Kosovo and Metohija.