First time to Switzerland

Your train from Paris to Switzerland should be the TGV-Lyria, which you should buy as far in advance as possible (90 days I think, but it can vary), in order to get the best price. Travel to Basel.

You might benefit from a Swiss Half Fare Card if you are using the lifts and mountain railways in the Berner Oberland, and especially if going to Zermatt for a day of glacier skiing. You can buy it at Basel train station for 120 CHF, then all the rest of your tickets and lifts will be half price.

From Basel there are frequent trains to get you to the Berner Oberland. At least 1 every hour and probably more. Suggest staying in Muerren for the views and hikes.

In the Berner Oberland area in Lauterbrunnen close to train station is a very nice youth hostel. Ck it out or also chalet Murren in Murren where u can hike easily up or down or take funiculars. But reserve early as they are very popular and an xcellent value.
With re to Zermatt Matterhorn, save for anotherr time. U can ski at berner oberland.

I'm thinking the previous poster meant "Chalet Fontana" in Murren. That's where we always stay. You don't have to worry about which train company in Switzerland to use. They're all integrated and all you have to do is look at www.sbb.ch/en to see the train schedules. It's super easy.

We just returned from Switzerland a week ago and stayed at the Hotel Bellevue in Murren for $150 a night with the best breakfast, view and hostess you could ask for. If you stay in Murren, you are staying IN the Alps. If you stay in Lauterbrunnen, you are staying in the valley of the Alps.

And it is very easy and fun to get to Murren. You take the train to Lauterbrunnen, transfer to a cable car that is just across the street, which takes you to another small train that takes you to Murren. It is only about 20 minutes total to get to Murren from Lauterbrunnen but a world of difference. (I know is sounds complicated but it isn't; just ask at any train station ticket window and they can explain it to you and give you a schedule. And the Swiss trains/cable cars are all synchronized and on time ALL OF THE TIME...they are a joy to use.) And there is lots of wonderful hiking all around Murren.

I would NOT stay at Gimmelwald not matter what Rick Steves says. My husband and I hiked there from Murren and there is NOTHING in this town. To get any groceries or anything else you would have to take the cable car back to Murren.

Another vote for Murren! We loved our stay at Chalet Fontana! If you hike in Murren, etc and have to leave to overnight in the valley, you will not want to leave the spectacular views!

U can ski at berner oberland.

I'd like to know where you do that in September.

But doing a day trip from Muerren to Zermatt could be problematic. It takes 3 hours to get there, so if you start at 6:00, you will not get there until 9:15, then you have to rent equipment, then get a bus or electric taxi to the other end of town to get the first of several long lifts to get to the glacier.
Click on the link at this site for summer lift schedule.
http://www.matterhornparadise.ch/en/timetable

Note at the bottom:

Last mountain run from Zermatt for snow sport enthusiasts 12:20 (Aug through Oct)

Last lift ride on the glacier lift about 14:00

If you are serious about skiing for a day, get there the night before so you can get going first thing in the morning. Summer snow gets quite sticky around noon, thus they shut it down shortly thereafter.