Input on Itinerary

Looks good to me. Check out Hallstatt Austria as well. Exploring the hillside trails above the town is really beautiful and the engineering they've installed to keep the town from washing into the lake is impressive.

In Mürren I suggest hiking up to Schilthorn and taking the tram back down. I did that a few years back and really enjoyed the hike.

You will probably benefit from a Swiss Half-fare card and a Berner-Oberland Regional Pass or a Jungfrau Region VIP Pass. The latter two are options in the Berner Oberland. It is an amazing area! We've been 3 times and already have a hankering to go back. You have to do the math based on what specific transportation you will use.

I really wanted to go to Hallstatt, but it seemed too much to squeeze in. Is Murren a good base to see the Berner Oberland?

"Is Murren a good base to see the Berner Oberland?"

It's a wonderful base. Others have other preferences, but I stayed in Mürren and was very happy about this choice. Some very nice features are the great views from town (and from my hotel room), the availability of a small supermarket and an ATM, and the number and quality of restaurants (they charged the usual Swiss high prices, but the quality of the food was quite high as well).

Gimmelwald is too small for me, with only a few restaurants and no ATM or supermarket. Lauterbrunnen was not nearly as nice a town as Mürren, although it does have all the needed facilities, and being in the valley it is equidistant to go up either side (but you miss the views of being up high that you get in Mürren). I didn't see Wengen, the option on the other side of the valley.

As I said, others have different opinions and experiences. Do read about all of these options; as long as you don't stay in Interlaken, you can't lose - they're all good.

Thanks Harold. From what I've read, Murren seems like a good base for the reasons you've listed, plus it's pretty accessible to the other towns in the airport.