Originally Posted by
ajax
The train ride to Sargans is lovely; should take you 70-80 minutes.
There are lots of nice walks to take in Zurich as well. The park on the east side of Lake Zurich (Zurichsee) is quite pleasant.
If you like chocolate, you could do worse than visiting the Lindt museum.

+1. The free samples in the Lindt factory are a nice taster, plus they have a fully stocked shop. It's also right next to the lake, for a nice walk.
Liechtenstein is nice, and a new country, but if you're flying out that night, then it'll be a bit risky.