Train from Paris to Murren

Ask your favourite rail company website. This will always provide the quickest route.
For example, the SBB (Swiss Federal Railways) website: https://www.sbb.ch/en

Enter From: Paris, to: Mürren Note: the correct spelling is Mürren, NOT Murren. If you haven't got a ü on your keyboard, either copy-paste or use the alternative spelling Muerren
Enter a date and a time, and click on "Search".
This will show all possible trains. For example (a random weekday in June):

Paris-Gare de Lyon dep 10:23, Mürren BLM arr 16:28
Paris-Gare de Lyon dep 12:23, Mürren BLM arr 18:28

There are earlier and later trains, I have just listed two examples.
If you click on any of the trains, it will show you where you have to change trains.
You can also buy tickets on this site. You get a "print-at-home" ticket sent to you by e-mail.

Thank you very much for your help. It is very much appreciated!

Note that for the first leg of your journey, say, Paris to Geneva (or Zurich) you will need to get a reservation for the bullet train. See www.seat61.com for info on this. The sooner you do it, the cheaper the price.

Viki,

That trip is actually quite straightforward, although it may initially appear complicated.

The 10:15 departure mentioned by Chris would be a good one to use (travel time 6H:13M 4 changes at Basel SBB, Interlaken Ost, Lauterbrunnen and Grütschalp). Gare de Lyon is one of about six large stations in Paris, so be sure to allow lots of time to get from your hotel to that station. There are two stations in Interlaken and "Ost" is the second one. One point to note is that you'll need to specify your destination as Mürren BLM (more on that later).

When you arrive at Interlaken Ost, you'll transfer to the Berner Oberland-Bahn. Be sure to check the digital display on the side of the car, as some trains split at Zweilütschinen. When you arrive in Lauterbrunnen, walk across the street from the station to the cable car station for the short trip to Grütschalp. When you arrive there, the small BLM mountain railway should be waiting, and you'll be in Mürren in a few minutes.

You can also use the Bahn.de (German rail) website to check schedules for all over Europe. If you want to buy advance tickets for the Paris - Basel segment, have a look at www.trainline.eu as it's a very user friendly site once you're registered. They don't sell tickets for Switzerland (yet), but you can either buy those when you arrive in Basel, or buy from the SBB site that Chris mentioned.

The options I listed involve a TGV high speed train (not a "bullet train") from Paris-Gare de Lyon to Basel SBB and Swiss internal trains thereafter. But you don't need to know that up front, that is the answer the train time website will give you.

You only need to buy a separate reservation for the TGV if you are using a rail pass. If you buy a normal ticket, it includes a reserved seat, and the seat details will be on your ticket. TGV tickets have discounts for advanced purchase and can only be used on the one train listed on the ticket. Swiss rail tickets are (in most cases) valid on any train on the date shown on the ticket.
The two different railway companies (SNCF and SBB) have radically different ticketing policies.

Thank you very much for all of the good advice. I am very grateful for your help!
Best regards,
Viki

You might want to check if your train from Paris to Basel will be affected by the rolling SNCF strikes which are for two days every week, for 3 months. Yesterday, for example, there were no TGV trains to Switzerland.

My crystal ball is cloudy about the chances of a resolution prior, but I can say that with not only the SNCF on strike but also several other simultaneous strikes involving Air France, waste disposal, energy and electricity, the industrial relations climate in France is not good at the moment, with both sides (the unions and Monsieur Macon) having dug plenty of trenches and brought in the big guns for a protracted war.

The calendar is in this BBC link :-- http://www.bbc.com/news/world-europe-43617033

I was able to get reservations from Paris to Basel, but I was wondering if reservations are recommended from Basel to Murren. I was considering getting Swiss Travel Passes. Any advice?
Sincerely,
Viki

No reservations are needed for your trip from Basel to Mürren. You buy your ticket or bring your Pass (and passport) and just show-up-and-go.

For information on Swiss Travel Pass prices and coverage, here's the Swiss web site (in English):
https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests.html
And here's the web site for the Berner Oberland Regional Pass (which is the region including Mürren):
http://www.regionalpass-berneroberland.ch/en/pass-and-infos/area-of-validity/

You'll need to compare those Pass prices with individual ticket prices from this web site, keeping in mind that the price you see is only with a Half Fare Card. (That's the default.) You'll need to double that to know the regular price.
www.sbb.ch/en

Different kinds of passes cover different kinds of things, so it all depends on your own travel plans.

I am in a similar situation. I noticed the train ticket from Paris to Basel is actually not really cheaper than a train ticket from Paris to Interlaken Ost. So I'm thinking of purchasing Paris to Interlaken. The only challenge is that the Paris to Interlaken Ost ticket delivers to UK address only. I would prefer to print at home or at station. Any suggestions? Maybe if I purchase not more than 60 days in advance? My trip is in July. Thanks!