After she was unable to form a Welsh-speaking school in London, the family chose to move close to the Welsh-speaking village of Rhoslan on the Llŷn Peninsula in 1950. The family took a stockholding that had no electricity, telephone communication or running water; neither had any experience of farming. Gwynn found a job working as a full-time lecturer for the Workers' Educational Association, from 1970 to 1979 in Anglesey, Arfon, Eifionydd and Llŷn, becoming according to her biography written by Deri Tomos in the Dictionary of Welsh Biography "one of the most important interpreters of science and technology – and their implications – to the Welsh speaking community." During her career, she became a freelancer, writing about 1,500 works on social development and science in the Welsh and English printed press. Papers she wrote for included The Scientist, New Scientist, The Observer, Scientific American, The Sunday Times, The Listener, New Internationalist and Y Faner. Gwynn also produced a weekly column of science in Y Cymro for 13 years and a weekly column on nutrition for Y Cymro for 10 years. She also appeared on radio and television.