Zurich to Lucerne to Lauterbrunnen to Italy

Best mode of transport is definitely train. Very frequent and the timetables are at www.sbb.ch/en. Being frequent, they are also expensive. Add up the full fare costs and if it exceeds 240 CHF per person, then a 120 CHF Half fare Card will save money as it gives 50% discount for everything, trains, buses, cable cars, boats, and even city transport like trams.

Suggest you go directly from Zurich airport to Luzern. There is a train station at the airport and you can get a direct train from there at least every hour, and at other times with connections.

If arriving by train, just take a connection to Luzern.

The only feasible method of transport is by train.
Mürren, and its outlying hamlet of Gimmelwald are only accessible by train or on foot, the road stops in the valley bottom at Lauterbrunnen.
You cannot drive into the centre of cities like Zürich and Bern. You would need to park and get public transport in.
Map of the Swiss Railways here: https://www.sbb.ch/content/dam/sbb/de/pdf/freizeit-ferien/ferien-kurztrips-schweiz/internationale-gaeste/sts-geltungsbereich_en.pdf
All rail lines in Switzerland, that is all the red lines on the map, have at least one train per hour.

And, hiring a car in one country and returning it in another either has a huge surcharge, or is simply not allowed.
If you are travelling through the Italian countryside it may be desirable to hire a car there, but not if you are staying in cities.

You can look up Swiss train times, including trains from Switzerland to Italy, on the SBB (Swiss Federal Railways) website: https://www.sbb.ch/en/

Are you entering Switzerland at ZRH and going straight to Luzern or starting the tour after a stay in Zurich? I'd suggest 2 nights in Luzern and the rest in Lauterbrunnen, although Interlaken shouldn't be ruled out. The Swiss transport system is integrated and schedules can be checked through the main railway website (even if they are by bus, cable car etc.) . A popular trip from Lauterbrunnen or Interlaken is the train to Kleine Scheidegg, there are two routes up which split at Zweilütschinen, one goes via Lauterbrunnen and the other via Grindelwald. Normally people do it as a round tour. Kleine Scheidegg is at the base of the Eiger. BUT the pass only gets a 50% discount on the Wengen-KS-Grindelwald section. It also gets 50% off the very expensive extension from KS up the Eiger.

https://www.sbb.ch/en/timetable.html

at the moment this site has some issues, looks like an upgrade may not have been tested first, so things may move oddly. Like everything else travel is Switzerland is expensive a travel pass might be an option https://www.swiss-pass.ch/

Is the flight back from Milan? It's very easy to reach from this area of Switzerland. There are direct trains from Spiez (but use the Kandersteg route not the new tunnel which goes under the scenery). Swiss Passes go as far as the Italian town of Domodossola. You can stay in Milan, not worth spending time going beyond. Or if you wanted scenery not city try the lake town of Stresa between the border and Milan. You can reach Malpensa airport without going into the city

The Berner Oberland Regional Pass covers all modes of transportation 100 %, including the cable cars, trains, ships, and buses, in all the places you mentioned except for Zurich to Lucerne*, and 1/2 price from Kleine Scheidegg up to the top of the Jungfraujoch, 1/2 price from Murren up to Schilthorn, and 1/2 price for Mount Titlis cable cars (near Lucerne). It costs 310 Swiss Francs for a 6 day pass, or 350 for an 8 day pass.You can buy it at the Lucerne Tourist Information office (Tourismus) by track 3 (your train from Zurich will pull into Luzern's track 4) for the rest of your journey (or any Tourist Office in the BO region).
*It doesn't include excursions near Lucerne like Mount Pilatus or Rigi or Lucerne Lake. The BO pass does include the train to Bern from Lauterbrunnen, however. I don't know your reason for wanting to visit Bern on this trip, but Bern isn't on the way to Lauterbrunnen if you take the gorgeous scenic route (via Brunig).
http://www.regionalpass-berneroberland.ch/en/

Since Lauterbrunnen, Mürren, and Gimmelwald are all in the same area, you only need to pick one for your hotel base to visit all three.

I agree that 2 nights in Luzern should be sufficient. The rest of the nights you could stay in the Lauterbrunnen area and visit Mürren, Gimmelwald, and Bern from there.

Thanks Sam, Chris F, SteveB, LindaL, for all you valuable info. If after spending 2 nights in Lauterbrunnen with side trip to Grimmelwald and Murren would you guys suggest taking a train to Laussane and do a side trip to Geneva, St. Moritz, Zermatt for 3-4 nights? Is this enough time? Any suggestions? Thanks

3/4 Days is not enough time for them all.

• Lauterbrunnen and Mürren are roughly in the centre of Switzerland.
• Lausanne and Geneva are to the west.
• Zermatt is to the south.
• St Moritz is way over in the far south-east of Switzerland.

I think you need to pick one, possible two of these, but no more.
If you want to end up in Zürich, you could go:
1) South to Zermatt - 1-2 nights
2) East to St Moritz - 1-2 nights. This is the route of the Glacier Express
3) Return direct to Zürich.
Look at the map I posted last time: https://www.sbb.ch/content/dam/sbb/de/pdf/freizeit-ferien/ferien-kurztrips-schweiz/internationale-gaeste/sts-geltungsbereich_en.pdf

BTW it is Gimmelwald, no 'r'. Otherwise it gets confused with Grindelwald a much larger place in the next valley.
Lauterbrunnen to Gimmelwald and Mürren is not a "side" trip, it is an "up" trip. That area is very 3-dimensional!

We will skip Italy.

After Lautterbrennen we have 4 more days before we head back to Zurich what do you suggest to go to. Thanks

We will not do Zermatt or St. Moritz what other places would you suggest? Thanks

It's good that you're narrowing down your locations. The thing about beautiful Switzerland with the glowing green grass meadows below the snow-capped mountains, is that it's the frequent rain and often a thick blanket of cloud cover on the mountains that keep it so green. So that means that if you're only in Lauterbrunnen for 2 nights (1 full day) then you're likely to miss the spectacular views that you came there to see. Each view in that Jungfrau area is completely different, depending on from which mountain you stand. The Rick Steves Switzerland guide book describes each of the places very well. I recommend doubling the number of days you'll be there for each view that you want. So you'll see the Jungfrau Mountain peaking above the Lauterbrunnen cliffs when you're in Lauterbrunnen. You'll see a series of mountains from a different side of the Jungfrau when you're in Gimmelwald (a cable car ride above the Lauterbrunnen Valley). You'll see even more snow-capped mountains from Allmendhubel (a funicular ride above Mürren). That's just on one side of the narrow valley. From the other side, you can go from Wengen up to Männlichen and easily walk to Kleine Scheidegg and see the Eiger, Monch, and Jungfrau mountains in front of you the whole way. Or you can go up to the Jungfraujoch from Kleine Scheidegg, up on the glacier. Or you can go from Lauterbrunnen to Wilderswil and take the cog rail train up to Schynigge Platte and walk to the top where you can see a 360 panorama view of all the valleys and mountains around there. Or you could take the train from Lauterbrunnen to Kleine Scheidegg, enjoy the mountains and meadows view at the Grindelwaldblick outdoor cafe terrace with a climb-up lookout point. Or you could take the train from Kleine Scheidegg down to Grindelwald and the cable car up from Grindelwald to First and enjoy the different set of snow-capped mountains that you see from there. Or you could walk from First to Bachalpsee and enjoy the different mountain and meadow views in that direction all the way to the alpine lake, and take the cliff walk on your return to the First restaurant.
And I've barely scratched the surface of what you can see there. Oh yeah, Schilthorn mountain views from up above Gimmelwald and Mürren.

As for Luzern, you probably want to see its Old Town. You might want to take a ship to Vitznau and a cog rail up the Rigi Mountain for spectacular views of Lucerne Lake and the alps beyond. And you might want to go to Mt. Pilatus, nearby. And to Mt. Titlis where you can walk the suspension bridge beside the mountain cliff, ride a chairlift over a glacier and sled or snow-tube, if you're so inclined.
Good luck with your planning!

I'd spend one more day in Lauterbrunnen, then take the train to Montreux or Vevey on Lac Leman (Lake Geneva), via Zweisimmen for the most scenic way. Skip side trip to Geneva, unless you want to tour CERN. Back to Zurich via Lausanne and Bern.

If you take Sam's advice and take the scenic train ride to Montreux, be sure to visit Chillon Castle, nearby!

Thanks again Sam and LindL. So we will be staying another night in Lauterbrennen. Train to Geneva or Lausanne (Chateau de Chillon medieval castle) stay 2 nights then fr Geneva fly to Paris and stay for 2 nights to head back home on the 10/1. Any other info that you can give? Much appreciated (:

We will fly home from Paris instead of Italy. Thanks

We will fly home from Paris instead of Italy. Thanks

Don't fly from Geneva to Paris - take the train right from Lausanne via Geneva. Much faster end to end; in particular, getting from the Paris airports to the center of Paris takes time and/or money.

Do book these trains in advance; the price goes up the longer you wait, and they can sell out.

Thank you guys for all your suggestions. 👍🏼 We extended our stay. We took a train from Geneva to Lyon and from there went to a few places in South of France and then train to Paris stayed a few days then flew back to the US. 😀