Jan 23, 2015 - 1:42 PM
I would recommend to stay in either Lauterbrunnen or Interlaken, not both. They're very close together, and changing hotels will take precious time you could spend sightseeing.
i) Don't do this on a fixed day, but first check if the weather is fine so that you can enjoy the views up there. If it's not, you can still go the next day. It's a full day trip if you take your time, but you can also add a short hike like Lauterbrunnen - Stechelberg or Grütschalp - Mürren. Further information can be found on the Jungfraujoch page. The local tourist office will be able to suggest more trails that are open in Winter.
ii) A 4-day Swiss Travel Pass would suit your needs, but you can also consider a Swiss Half Fare Card. Please see the links for all details. You can buy these passes online, which is cheaper than at the airport. Please see here to check prices and points of sale.
Have a great time!
Last modified on Jan 23, 2015 - 1:44 PM by Arno