Zermatt is 3:14 from Zurich main station (see www.sbb.ch for train times). If you haven't been, the town of Zermatt is very cool and the train ride is quite scenic. Look into buying a Swiss Transfer Ticket - it'll definitely give you significant saving to Zermatt - the first class option I would say is worth getting. One night stays during ski season might be hard to come by given a lot of people head there for week long stays. Coeur des Alpes is my favorite spot to stay - why can't they make that a Hyatt property?