In late June I stayed in Murren and Luzern. I provided a trip report at the Switzerland Q&A page. This post elaborates on my experience in Isenfluh. I'm a little reluctant to mention it because it's a hidden gem that is very untouristy.
Isenfluh is a hamlet at the northern end of the Lauterbrunnen valley. It can only be reached by vehicle or foot. I took the yellow Postal bus from the Lauterbrunnen station. It takes about 10 minutes. If you take the bus, board early. It has about 12-15 seats. One trip had 27 passengers. Part of the drive is through a spiral tunnel inside a mountain. Going down my GPS indicated a change from 133 to 116 degrees, or a change of 343 degrees. I would hate to make the drive in winter.
Isenfluh has better views of the "famous three" than Murren or Gimmelwald. There's one hotel and a restaurant. There are some good walks from there. A small cable car goes to Sulwald. It holds eight people "or one cow." I was the only one who bought a round trip ticket, so the station manager showed me how to operate the cable car.
Sulwald has great views too. Everyone else went there to take a walk. A popular destination is the Lobhorner. If you've been to Wengen you've probably seen it; it looks like five fingers sticking up from the ground. The Lobhorner hut looks popular.
I successfully operated the cable car to get down. Basically, it's only necessary to push two buttons. One opens the door and the other signals the station operator that the car is ready to go. After signaling that I was ready I let in a Swiss woman who couldn't open the door. The cable car is really controlled by an operator at the lower level station.
In sum, Isenfluh has great views and walks. It has few tourists. I recommend it as a day trip.
P.S.,
If you have a Swiss Pass, going to Chillon castle in Montreaux is a reasonable day trip on a rainy day.