Train from Milan to Lauterbrunnen

Mike, I assume you mean a Swiss Rail Pass, and you will be buying a discounted ticket in advance for the Italian section (Milan to Domodossola).

No you cannot buy a Swiss Pass at Milan station, you can only buy it at Swiss airport or border stations, which includes Domodossola, but you don't want to waste time and get off the train there.
You can also buy them before you leave home, on the SBB (Swiss Federal Railways) website here: https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests/swiss-travel-pass.html
You will pay the same price as buying the Pass at a station, but if you buy online you get a "print-at-home" ticket.
Various other websites also resell them, but you may pay more in that case.

A Swiss Travel Pass might not be the best value for you. For one thing, you may be able to get "Special" advance purchase nonrefundable ticket from Milan to Spiez for very good prices. Train will be direct. At Spiez, it is a short connecting train to Interlaken Ost, then a connecting train to Lauterbrunnen. Half fare cards may be what you want, or a Berner Oberland 4-day day pass. Where are you going after Lauterbrunnen?

By the way, a Berner Oberland Pass will cover the trains from Swiss border all the way in to Lauterbrunnen and then almost everything in that area including cable cars. However, you have to ask for the slower train up to Spiez for full coverage. I just did it last August.

We will be heading to Zermatt after Interlaken area. Will be joining a National Geographic Train Tour around Switzerland.

I was just taking a look at this tour. It appears that it includes the train from Zurich airport to Zermatt. Therefore, it seems that you could pick this train up in Spiez when you leave.
I see that the cost of a nonrefundable, non-changeable Mini ticket from Milan to Spiez is 34 CHF per person. The cost with a Swiss Travel Pass with no restrictions is 28 CHF per person, so the pass is not saving that much for that leg.

Depending on what you want to do in Lauterbrunnen, a Pass or Half Fare Card may be wasted money. If you want to go to the Jungfraujoch, a Half Fare Card might be indicated. The Half Fare Card costs 120 CHF per person, and it pays off if you have more than 240 CHF. A round trip from Lauterbrunnen to the Jungfraujoch is about 190 CHF per person.

If, on the other hand, you only plan on a few lifts for hiking, just pay as you go will cost you less than the very expensive 4-day Travel Pass, at 270 CHF per person, and that does not cover everything. Going to the Jungfraujoch, it is only good to Wengen, then you get a 25% discount for everything above that. The Travel Pass does include the Schilthornbahn all the way to the top.

The 4-day Berner Oberland Regional Pass is 250 CHF. It includes trains up to Kleine Scheidegg, then 25% discount to the Jungraujoch, but only 50% discount on the Schilthornbahn above Muerren. Also the train from Brig, you must get off the EC train there and take the Loetschberger train that uses the older route over the mountains (more scenic) rather than the newer, quicker route that the EC train uses that goes under the mountains in the Loetschberg Base Tunnel.

Pricing up all these options is a bit of a chore, but blindly choosing a Swiss Travel Pass is often the most expensive option.

Wow! Great information. So if I understand correctly, we will need Italian train tix from Milan to the border, then Swiss train tix, or passes, for the duration of the Switzerland trip? Even though you indicate the 4 day pass for Interlaken may be more expensive, will having the pass make our travels easier, or more convenient? If not, we will probably pay as we go as you suggested. Also, how do we best get more info on the various hikes, and other options for things to do, while in the Lauterbrunnen area? Hopefully, that will help us decide what we can do while there. Lastly, any recommendation for a hotel in Lauderbrunnen? Thank you!
Mike

If you buy at the Trenitalia site, they can only sell tickets as far a Spiez, no interconnecting trains inside Switzerland. There are 3 direct EC trains a day from Milan to Basel which pass through Spiez, so they can sell the tickets. The "Mini" advance purchase go for 29.90 EUR at http://www.trenitalia.com/tcom-en

But SBB can sell you tickets all the way from Milan to Lauterbrunnen. They sell the same Mini tickets for the Milan-Spiez portion for 34 CHF, the same equivalent price. You can buy at https://www.sbb.ch/en.

With a Swiss Travel Pass, you don't have to buy individual train tickets, except the Italian portion. At the SBB site, you can see the box marked "Reductions for Switzerland" and slect "G.A." and you will get the price with the Swiss Travel Pass.

Here is the map of validity for the Swiss Travel Pass. Look at the routes with the "1" in a circle where you only get a discount. There you still have to buy tickets.
https://www.sbb.ch/content/dam/sbb/de/infotexte/uebersichtskarte-sts.pdf

will having the pass make our travels easier, or more convenient?

not a lot, really.

All Swiss ticket agents, whether in the train stations or at the base of a cable car or on a postbus speak enough passable English to get you where you are going efficiently, fairly, and fast. Using the machines if you prefer is easy too after a tiny learning curve. They speak English too, if you press the flag symbol.

And if you buy at the time of need you only buy what you need, nothing spent on maybe.

Can you recommend a hotel in Lauterbrunnen?

I went to the SBB site to look at tix from Milan to Lauterbrunnen. There are multiple choice for Milan and also for Lauterbrunnen. How do I know which station to choose?

I am sure if you do a search of this forum you will find some recommendations for lodging in Lauterbrunnen.

If you want to consider staying up in the mountains, may I suggest checking out Murren? It is a short funicular and train ride up from the valley where Lauterbrunnen is situated. The views are positively stunning! We stayed in a lovely bed and breakfast run by a British woman- Denise at Chalet Fontana - http://www.ferntree.ch/chalet/fontana.htm.

There are also a number of hotels in town that have good reviews in this forum.

Enjoy your trip. Switzerland is stunning!

First, I'm not sure, but I think you are confusing "rail pass" with "ticket." If you are taking a single train, you buy a single ticket. If you are taking multiple trains, sometimes a rail pass can save money and/or hassle, and sometimes it is actually more expensive than single tickets.

Within Switzerland, there are very few discounts for advance purchase of tickets, and very few trains that require reservations. So, there's no problem just buying tickets as you go, as Nigel says. However, if you are taking more than a few trains, or are definitely taking some of the very expensive ones (such as the Jungfraujoch), a pass or Half Fare Card can be a very good deal. Note that when checking prices on the Swiss Rail website https://www.sbb.ch/en/home.html, it assumes a Half Fare Card; click on "no reduction" to see what you'll pay with no card or pass.

Italy is different. Many trains require reservations (which you get when you buy a ticket) and the reservation means the ticket is good only for one specific train - not the one 10 minutes earlier or an hour later. Furthermore, on those routes that require reservations, the tickets can be much cheaper if you buy in advance and accept non-refundable and non-exchangeable tickets. Tickets from Italy to Switzerland work this way as well.

Since you are on a National Geographic tour, I assume that they will be taking care of much of your transportation. So, you only need to pay for transportation before and after the tour. Is this correct? If you can give us a day by day outline, people can give more tailored advice (such as: 3 days in Venice on our own, a day in Milan on our own, 4 days in Lauterbrunnen on our own, then going to Bern to start a 10 day tour ending in Zurich, then 1 day on our own in Zurich before flying home)

As for where to stay in the Berner Oberland, I liked Mürren more (and had more delicious food there), but Lauterbrunnen was a bit more convenient for both sides of the valley. All four villages (Lauterbrunnen, Mürren, Gimmelwald, and Wengen) have their fans. Realize you can't lose wherever you stay. In Lauterbrunnen in 2017, I stayed at the Hotel Silberhorn https://www.silberhorn.com/en/, and in Mürren in 2014, I stayed at the Hotel Edelweiss: http://www.edelweiss-muerren.ch/en.html?cHash=d1e8f77b350621ba66d6f81b285b68fa. Both were fine, and I'd certainly stay at each again. Note that the Silberhorn is up a bit of a hill and has no elevator, while the Edelweiss is a nearly flat walk from the station and has an elevator.

Mike, I sent you a private message about a dozen hikes around the Lauterbrunnen area.
Just click on your name in upper right or your name in a message.