After backpacking and hitchhiking and taking boats across the Americas, Sanderson worked with the International Red Cross in Nigeria during the Biafran War in 1967. He was in Vietnam a few months after the Tet Offensive, posing as an aid worker and journalist, and traveled through Yemen during the North Yemen Civil War. In Kisangani, Democratic Republic of Congo, he met the white mercenaries who had been hired by the government to fight the warriors of the Simba Rebellion. And in Bolivia, he launched a hospital for the poor in the town of Sorata, but was detained by the authorities during the René Barrientos dictatorship.