Between Bern and Munich

I am planning a trip and have four days to spend between Bern and getting back to Munich where I fly home. Where should I go? I have been to Munich and salzburg already and will have seen Bern, and have done the Bavarian Alps and Neuwanstein. Places I am thinking of are Liechstenstein, the Salzburg Lake District, Lake Constance, or possibly going west toward the Jura region and then going from there to Munich at the end (trains). Anyone have thoughts on this itinerary? I will be train dependent, but prefer small towns/countryside.

Try Lake Constance if you are into nature and such.

The flower island Mainau is very pretty, as are the cities Friedrichshafen, Lindau (German side) and Romanshorn (Swiss).

Friedrichshafen used to be the zeppelin city, they have a pretty museum around this part of their history.

In the Austrian corner near Bregenz you got the Pfänder, a big mountain with a great view over the Lake. Take the cable car up and visit the bird of prey show or just enjoy the view.

http://www.pfaenderbahn.at

The Rhinefalls are relatively close too, you might want to take a look.

All I would add, is that if you've time - a trip to Geneva is a must. It's a lovely city - and the surrounding area is equally beautiful. Anywhere throughout Switzerland is reachable in well under a day, even by train. It's a very small country.
Enjoy your trip.

You said Geneva is a must, which one you would rather go between Zurich and Geneva?

Is Interlaken is a must too?

Please help.