Hi Springers -
Welcome to My Swiss Alps. Good time of year to visit. Not quite as full of tourists as August. ;-)
<<"Also whether it is easy to stop off on the train routes, such as to spend a few hours at Thun, before proceeding to Lausanne.">>
You have pleasant surprise waiting for you.
If you use point to point tickets, they are good for one day.
You can get on and off any place along the route and get back on later.
There are trains almost everywhere once per hour. On main routes, you can look for two or more per hour. Interlaken Ost has good mainline connections with the rest of the rail network.
Use the timetable to figure out timing and options. Make sure to read the introductory page at this link:
Also whether it is easy to stop off on the train routes, such as to spend a few hours at Thun, before proceeding to Lausanne.
Here is a comment that I just posted in another thread:
<<"There is a lot of useful material in the time table. Enter any journey - start and destination, date, time. You will get a list of four journeys. Click on the "+" sign to the left of any one entry. You will get a lot of details for that journey. Use the footnotes to see intermediate stops, and get a map of the journey. You may need to uncheck some options with the map. The map can show you a local street map near the stations at the start and finish. Be careful with the posted fares. As noted on the instruction page, those are generally half - fares, because most Swiss have a half-fare card.">>
If you choose certain kinds of rail passes, you don'y need tickets. Just get on and get off.
Arno and Annika are experts on all the rail passes, but here is a start: www.myswissalps.com/tr ain/ticketspasses
Almost any destination in Switzerland is good for several days of "touristing." First timers usually start in the high Alps...Jungfrau region....or. Luzern. Most choose Montreux over Lausanne, if you are going to be in that region.
Explore the "Where to go" links for regions and towns:
Since you have picked Wengen, which happens to be my favorite in the Jungfrau Region, you will find this brief report of some value:
It is important to allow several days in the Jungfrau region, because high clouds can ruin trips at higher elevations. The weather changes rapidly, and the Alps make their own weather. The regions link on the Bernes Oberland gives a lot of contingencies for less than perfect weather. Altitude is everything...the clouds often come in layers. It may be cloudy at 1500 meters and clear above 2000 meters, for example. There are plenty of resources for weather info in Wengen...tourist ofice, train station, hotel reception, etc.
So, for two weeks, your idea of a few days in/around Luzern, a centerpiece of the Jungfrau Region, and a short stay near lake Geneva is a good plan for variety and a range of experiences.
What are your interests....scenery, trains, walking, hiking, sports, museums, arts and music, country villages, cities.....?
Here is one thing that you must not miss near Wengen:
Attached are a couple of photos from along that route. Be sure to walk toward Kleine Scheidegg... the views of the Eiger add tremendously to the impact.