Best train route from Zurich to Varenna, Italy

Not necessary if you don't want to. You can also take the Cisalpino route that heads south from Zürich, via Arth-Goldau, Bellinzona, and Lugano to Como. One stop past Como, at Monza, you change to a train for Varenna. Or maybe there are boats from Como to Varenna? Another route from Zürich goes via Chur and St. Moritz, but this one has a bus connection along the way. Milan route is fastest, by about 1 hour (5 hours instead of 6). You can view the routes and schedules at www.rail.ch.