<<"Basel Airport and then go to Lucern like a good base 2 or 3 days doing your page suggestions.I'm a little concern staying in a little base likeMurren or Wengen and if the weather is bad not have the possibility of going up the mountain..Perhaps is better for me to take the Golden pass and go to Montreaux but were is better to stay one night in the route? or were to stop..and see which part of thre route is better for scenic views? Then go the last day only to Geneve to take the flight...Do you think is ok?">>
All of that makes sense.
The Jungfraujoch, or, less aggressively, via the cograil train from Lauterbrunnen, the villages mentioned actually can be reached from Luzern in 3 hrs 15 minutes to Kleine Scheidegg. Trains every hour at xx05. The route is through the Brunig Pass, which is quite scenic.
It is along haul, but the latter parts in the LBValley near the Jungfrau are scenic, and the views from Kleine Scheidegg are pretty good. It could be a way to sample the area.
With your information about the itinerary, it is possible to add some ideas. First of all, with 7 or 8 days available, you can easily select two bases, possibly even three bases. Luzern is an excellent starting point, as you have seen.
And, you have begun to put together some possible rail routes.
There are other possibilities from Interlaken, so we could discuss that if you decide to stay in the Interlaken/Jungfrau region. One that I like is the very scenic ride through the Kandertal (via Kandersteg, not the new lower level and boring tunnel) to the Rhone Valley at Brig, thence along the Rhone to Montreux, Lausanne, Geneva. It would not make much sense unless you were staying somewhere close to the route, so its is just for background information.
I'd like to address your interest in getting close to nature and walking in smaller towns. Since it is Winter, you will not see the kind of scenery that I have photographed in the attached images taken in the Emmental. Although no single town is worth a journey, the visit to a few Emmental villages that are close together, along with walks, puts you in the heart of old Swiss country culture, and has very nice villages. If it were Spring or Fall, I'd recommend it. It is between Bern and Luzern, and easily accessible from Basel, as well. But, "nature"is likely going to be a bit drab and cold in mid-December. (Sometimes you get sunny days...can be very nice for walks.) See pictures.
There are quite a few smaller towns and villages in the Western part of Switzerland that you could reach, especially if you stay a day or so in a location north of Geneva.....
I'll not post links at this time, but you can search this web site and MySwitzerland.com. I'll try to add some more information later.
I have visited all of these places, often for day trips or a few hours, and enjoyed walking around them. I have stayed at many of them. All are accessible by public transportation; most by train, some require a bus.
Get out your map. There are a lot of secondary/local rail lines in the area north of Lausanne, and they offer nice views of the country while you ride to many of these places.
For that matter, the lake side community and walk/promenade/trail below Lausanne, at Ouchy, is a long time scenic harbor and lakeside destination.
Look at a map and zoom in on Ouchy by the lake.
There are many hotels and restaurants. The walk along the lake continues most of the to way Vevey (with a few gaps requiring walking on roads.) You are walking directly below the vineyards, and the views of the lake,vineyards, small villages and mountains are very attractive. There is train line with you can pick up at, for example, Villette or Cully after you have walked a few km. Or you can catch it closer to Lausanne, but for example, at Lutry, the train station is up the hill a bit. At Villette and Cully the stations are very close to the walking route.
The old city down by the river in Fribourg
Schafis/Ligerz/Twann on the Bielersee
The old city part of Bern, with a walk from the station down through the old town too the Nydegg Bridge, and up to the scenic overlook at the Rosegarden. Not so many roses in December...;-(
Yvoire, in France, on lake Geneva
As far as I am concerned, and as far as the Unesco World heritage Organization is concerned, the most attractive village in Switzerland is Guarda. That, and the other Lower Engadine villages of Ardez, Ftan, Scuol, Sur-En (tiny) make a good destination. They are quite out of the way in the southeast corner of Switzerland, and probably don't fit your schedule. The lower altitudes (Scuol) are probably snow free, but the peaks and ski areas will probably have skiers on them in late December.
Three pictures attached.