Travel itenary help...

"Ideally spend two days Interlaken area (some saying stay beyond this place)"

No, not some - almost everyone will tell you not to stay in Interlaken, which is near but not in the Alps. Stay in the Lauterbrunnen valley area, in the town of Lauterbrunnen (on the valley floor), in Wengen (up one side) or in Gimmelwald or Muerren (up the other side).

Furthermore, don't spend 2 nights in the Alps and 3 nights in Luzern, but the reverse. The activities in the Alps are very weather dependent, and mountain weather is both unpredictable and rapidly changeable. You want as much time there as possible, just in case you get a cloudy day or rainy afternoon. There are things to do during the clouds and rain (one reason the region is so great), and you will want to be flexible, so when the weather turns you can pivot your activities to match.

Trains in Switzerland run every hour or more frequently. No reservations are needed.

Yes, you can easily day trip from Luzern to Zurich (about an hour each way).

I'll leave the train pass questions to others, except to say that it's always complicated, so you're not alone in wondering which is the best deal.

Do you have Rick Steves Switzerland? If not, get it ASAP. He has all the information you need for this trip.

Thank you Harold . Is it a book ? I will check it on amazon.

The Swiss have perfected train travel. You will be amazed by the number of routes and the precise timing of departures and arrivals. You definitely want to do Switzerland by train!

In the Interlaken Area (Bernese Oberland), you want to stay close to Lauterbrunnen Valley - though train travel is so quick and efficient that even a stay in Bern makes Jungfrau within fairly easy reach.

Lucerne to Zurich is a frequent and quick train ride - less than an hour.

I think you can get a free family card for your 13-year old, as long as they are accompanied by at least one ticketed parent. Consider a Swiss flex pass for 4 non-consecutive days for 310 CHF adults, 265 CHF youth 16 and over. This is likely a decent alternative, especially if you have a day in Lucerne where you won't travel by train. But also visit Eurail.com, SBB.ch or Swiss-pass.ch or one of the other vendors and price out individual tickets for your proposed itinerary. For instance, I believe it's about 35-40 CHF from Zurich to Interlaken. You might find that individual tickets are less expensive - though a pass is so nice for the convenience and hassle avoidance.

Thank you, Bradley for your prompt response. You are all very helpful.

Well, Harold pretty much took the words right out of my mouth, though I was going to say "EVERY experienced Swiss traveler will tell you NOT to stay in Interlaken". I also agree with Harold about spending more time in the Lauterbrunnen area.

Lucerne is certainly worth a look, and your teens will likely enjoy the mirror maze there (mine did). It is in the Glacier Garden, immediately to the left of you as you look at the Dying Lion monument.

https://www.gletschergarten.ch/en/mirror-maze/

I would re-think taking a day trip from Lucerne (wonderful) to Zurich (mildly interesting). It's not what I would do given the short time in Switz.

For a 6-day pass, consider the Berner Oberland Pass:

https://www.regionalpass-berneroberland.ch/en/pass-and-infos/pricing/

I wouldn't get enamored with "Golden Express". It's nice to see Swiss scenery from a train, but it can't compare to hiking through it. Train: see a sight from one direction for about 60 seconds. Hike: see a mountain vista from various viewpoints for hours. With that in mind, I'm private mailing you our dozen favorite hikes in the Lauterbrunnen areas. They have been "teen-tested" by my own teens. Click on your name in the upper right to read your forum mail.

Thanks a lot. You all made our day. Thanks Steve for making this useful forum.

Rick's new Switzerland book was on sale on his website. I just received mine on Tue. However, now it is back to the regular price. The other site that has it on sale is target.com. It is $14.57.

Not counting the day you arrive and the day you depart, seems like you only really have four days in Switzerland. Depending on the times of your flights, could you see some of Zurich either the day you arrive or the day you depart?