if you are in Switzerland don't miss the canton of Valais and go straight to Martigny (my hometown) from where you can head to France and Italy by train and bus, through nice mountain sceneries.
Don't forget to enjoy the typical cheese meals like fondue and Raclette and the tasty white and red wines available there (Fendant, Johannisberg, Petite Arvine, Malvoisie, etc) I'me sure you'll enjoy the experience.
Excursions from M A R T I G N Y in Valais :: Switzerland
EDIT: Martigny is just 1/2 an hour by train from Vevey heading to the south. Worst a visit.