train travel in Switzerland

You are definitely NOT the only one who finds the train pass thing confusing. There is a bewildering assortment, especially for Switzerland.

I am not a fan of the 2-country France-Swiss pass. For one thing, it is only available in 1st class, which isn't necessary in Switzerland, or even available on some trains. And as Steve mentioned, it doesn't cover some of the mountain trains and lifts. Also, some private trains require a supplement.

There are number of passes that might work for you, but it depends on how many days you will be in Muerren, whether you intend to do some local excursions by train and/or boat, whether you plan to go up the Jungfraujoch, and whether there will be others with you (some passes offer 15% discount for 2 or more traveling together).

You might consider some kind of Swiss pass plus point-to-point tickets for France, starting with an advance-purchase TGV ticket from Basel (or Geneva or Lausanne) to Paris.

As for which Swiss pass, if you define some of the parameters (how many days, how many people, other excursions, etc.) I can try to narrow the range of choices for you.

Train passes are confusing. I have bought a 30 day half fare card, last year it was 99 franc, which gave half fare on trains, including the one to Jungfrau. If it is 80 one way from Zurich to Murren, you would spend 139 (99 plus half of 80) using the half price card. But you could still use the card for the Swiss portion of the trip to Paris and for any mountain trains or lake boats you use in Switzerland. You may want to figure out the point to point tickets, compare the costs to the various passes, and see if the half fare card is an option that makes sense. Spending some time doing that may save you money to use for wine or cheese. Have a great trip.