Feb 10, 2012 - 4:02 AM
Hello yatchee1, and welcome! Since you'll be making rather long train trips from Bern, an 8 day Swiss Saver Pass would be the most obvious rail pass choice. It will cover all your trips in regular trains, buses and boats, and grant discounts on mountain transportation. The online timetable allows you to plan each trip.
You've already mentioned some of the most importation (tourist) towns to be reached from Bern. The Bernese Oberland and Wallis day trip overviews suggest lots of placed to visit near Interlaken and Zermatt. Highlights are the Jungfraujoch and the Schilthorn near Interlaken, and the Gornergrat near Zermatt, offering a great view of the Matterhorn. (Zermatt and the Jungfraujoch are very different. Zermatt is a town at the foot of the mountains; the Jungfraujoch is a railway station, viewing platform and tourist attraction high up in the mountains).
Does that help you out a bit? Kind regards,