Swiss Trip

You must travel through Interlaken to get to Lauterbrunnen and then to Wengen. There is little value to actually visit Interlaken as a destination. Zurich is also another place that is really not a tourist destination. It's just a banking city.

If you spend your time in Lauterbrunnen you will be in between Wengen (Jungfrau) and Murren (Schilthorn).

I think I'd split the time between Lauterbrunnen valley and Luzern. In Luzern there is plenty to do(city center, bridges and river, boat rides, trek to the top of one or more of the three mountain tops, transportation museum, churches, great art museum), if you have time left, I'd recommend a day trip to Bern. If you feel like you need a third place to stay, perhaps Lausanne on Lake Geneva--wine, cheese, tour of Chateau Chillon.

With only a very short eight days, I agree with the previous suggestion to focus on the Lauterbrunnen Valley and Lucerne. If you stay in the town of Lauterbrunnen, you can easily take day trips to Wengen and Interlaken, as well as Mürren, Gimmelwald, Grindelwald, the Schilthorn or the Jungfraujoch. If you're planning to use a lot of mountain lifts, one of the many Swiss Passes may save you some money (which is important as Switzerland is expensive) - https://www.ricksteves.com/travel-tips/transportation/trains/switzerland-rail-passes .

I agree with two above posts. Skip Zurich and Interlaken. Luzern and Wengen or Murren.

Just agreeing with everyone else.

With only 8 days, go right to the Lauterbrunnen valley (the Berner Oberland). Stay in Wengen, Lauterbrunnen, or Muerren for 4-5 nights. From this base, you can see all of the sights in this area (no need to change hotels). You will have all the scenery and hikes you desire, as well as great variety. In addition to the more famous Schilthorn and Jungfraujoch, I really liked the Allmendhubel (great views and walking possibilities from there, and it's much cheaper than the higher trips like the Jungfrau).

Then go to Luzern for your remaining nights (plan at least 2-3). From here, you can not only see the very nice town of Luzern itself, but take excursions via boat and rail to Mt. Rigi and/or Mt. Pilatus.

From Luzern, you can take a train right to Zurich airport in 70 minutes for your return flight. In a short time, you will have seen some real highlights of Switzerland and had a fabulous time!

Interlaken has sex shops, jewelry stores, lots of restaurants (particularly Asian ones), large grocery stores (the Berner Oberland towns have smaller ones), department stores (came in handy when my day bag broke and I needed to buy a new one), and loads of tourists. Oh, and I found the Museum of Tourism mildly interesting for an hour or so. Unless you are looking for these things, you don't need to spend any time in Interlaken.

Thanks everyone for your valuable inputs and suggestions. After doing more research/reading we have made few changes to our original plan. Now we are flying in and out of Paris (1000$ less on air tickets). We will be spending about 3 to 4 nights in Paris and then take the train to Interlaken and will be staying in Wengen for 4 nights. PLanning to get the 5 days Swiss pass for internal travel in Switzerland.
What would be the scenic train ride that you would recommend (3 to 4 hours) ?
What website would be the best for booking the Paris to Interlaken train tickets?

Thanks

I took the Golden Pass scenic train. It runs from Lake Luzern to Lausaunne with Interlaken about halfway between the two. Its beautiful. I think from Paris, the quickest train route to Interlaken is thru Basel and then Bern. If you wanted, you could go thru Basel to Luzern and then Interlaken which would give you half of the Golden Pass route. I think it adds about 1 1/2 hours to your trip. A better option so that you are better rested might be to either to take a train ride while you are staying in BO OR do the northern portion, Interlaken to Luzern on your way back to Paris. I got this information from the website Rome2Rio which people on this forum seem to like. I too, find that it is very easy to use and for trying different options.

"What website would be the best for booking the Paris to Interlaken train tickets?"

For tickets from Paris to Basel, I'd suggest using www.trainline.eu . Note that there are about six large stations in Paris, so you'll need to note which station you'll be using. That trip will be via high speed TGV and you'll have reserved seats. You'll need to register on the Trainline website first (including payment information) but after that the process is very easy. They also have a smartphone app.

Unfortunately, Trainline does not yet sell tickets for Swiss trains. If you want to buy advance tickets, use the sbb.ch website. It's probably just as easy to buy your ongoing tickets from Basel to Wengen when you arrive there. There are frequent trains and you shouldn't have to wait long for the next one.

If you just want to check times and train solutions, one of the easiest websites is https://www.bahn.com/en/view/index.shtml .

One point to note when you take the Berner Oberlandbahn from Interlaken Ost to Lauterbrunnen. Be sure to note the small digital display on the car which indicates the destination. Some of the trains split in Zweilütschinen, and part of the train goes to Grindelwald. Be sure to board the cars going to Lauterbrunnen. When you arrive there, you'll transfer to the Wengernalpbahn cog wheel trains for the trip up the hill to Wengen.

It's generally a good idea to book the French high speed trains in advance to save money. The only caveat is if you are taking the train the same day you arrive Paris by plane, it is a little risky because your plane could be late and the ticket not refundable.