What Pass to buy

Looks like you have 12 nights, I’d add a night to the Jungfrau Region and stay in Wengen or Grindelwald instead of Interlaken, but you need to get your lodging ASAP for July. A lot will already be sold out. Wengen would be a unique experience in your trip, as it’s car free, which gives it a special feeling.

Munich (2 nights) - Lucerne (3 nights) - Wengen (4 nights) - Paris (3 nights)

It’s hard to suggest passes when you don’t have specific activities planned and you’re trying to cover 3 countries. Do you like to hike in Switzerland? Have you made a list of some activities you’re interested in? This will help with suggestions.

Have you got your hotel and transport arranged for the last bit -- the bit in Paris? I ask because you will be leaving on Sunday the 14th July. That's the national festival - what is called in North America, Bastille Day. Paris is always a focus, Saturday nights (the night before you leave) at hotels are usually busy, the Olympics are arriving in town and so is the Tour de France, so if you haven't got your hotel taken care of you need to ASAP. You may be shocked at the prices.

Also, as that weekend will be very busy I expect the trains in the lead up to the weekend will be correspondingly busy.

Do you go straight through Interlaken - Basel - Paris?

@Nigel - I did book my hotel for Paris from July 11-July 14 (July 14th checkout) at Hotel de la Bretonnerie. So that has been booked and prices are shocking.

Our plan is to take the train from Interlaken - Basel - Paris. I am planning to get the Half Price STP and Overland Pass. Can I book trains from Interlaken to Paris in advance? Also, as its going to be a super busy weekend. Any advice on advance booking on any activities. I guess I should book the Eiffel tower tickets and Louvre in advance.

One more night in Munich, one more night in Interlaken (and as wanderweg suggests, Muerren or Wengen would be better), and one more night in Paris.

You should buy your Munich-Luzern, and Interlaken (or other)-Paris tickets now, nonrefundable advance tickets getting the best price.
You can look at getting 6-day Swiss Travel Passes, beginning the day after you arrive in Luzern. the 16 1/2 yo is an adult, but along with the 22 yo qualify for the Youth STP at a discount.
https://www.sbb.ch/en/tickets-offers/tickets/guests-abroad/swiss-travel-pass.html

An alternative plan is to buy Half Fare Cards at 120 CHF each and 4-day Berner Oberland Passes. The kids get the reduced price without Half Fare Cards.
https://www.sbb.ch/en/tickets-offers/tickets/guests-abroad/swiss-halffare-card.html
https://www.berneseoberlandpass.ch/prices-tickets/

@wanderweg .. My kids may enjoy a bit of hiking, I am not the fittest living mankind but love to travel. Our plan is to visit the mountain towns. As first time Switzerland visitor at Interlaken -

Planning to visit the mountain sister towns - Luterbrunnen, Wegen, Murren, Harden Kulm, Jungfru and do the typical touristy stuff. At Lucerne - Staying in the city to visit Mt Pilatus and Rigi.

My question however is if we stay at Wengen will it be hard to take the train back to Paris on July 11. I think the train from Interlaken leaves at 6am towards Paris? I have to get to Paris by July 11 evening latest at that too by train.

The 8 am departure from Interlaken gets you to Paris at 1:38 pm. By the time you get to your hotel, you should be about ready to check in. You could depart Wengen at 7:13 am to catch it.

For your list, staying in Wengen would be better than Interlaken and as shared above, just take the 7:13 out of Wengen to do the 8 from Interlaken.

For your list you’ll also want the extra time in that area. You can combine Wengen > Mannlichen > Walk to Kleine Scheidegg > Jungfraujoch > Wengen for one day, another day Wengen > Lauterbrunnen > Murren > optional Schilthorn or Allmendhubel > Gimmelwald > Stechelberg > Lauterbrunnen > Wengen and your other day possibly Lake Brienz + Harder Kulm or in my opinion Brienzer Rothorn is much better than Harder Kulm and can be combined with Lake Brienz or skip the lake because you’ll have been around the lake in Luzern and instead do Schynigge Platte for that additional day.

Thank you everyone, I booked the passes.

HAS ANYONE STAYED AT EITHER HOTEL BERGHAUS OR HOTEL FALKEN IN WENGEN? WHICH ONE WILL YOU RECOMMEND. WE ARE A FAMILY OF 4 WITH 2 KIDS IN THEIR EARLY YOUTH.

I am so confused, I booked both for now as I did not which one will be right for us. One huge plus point for Berghaus is they are giving us 3 rooms, so each has its own bathroom which is great when travelling having not to share. It's a about $300 more that Hotel Falken in total cost.

I have not stayed at either, only note that the Falken is close to the train station, and the Berghaus is a bit of a walk, slightly up hill.