Hello kekueterman,
I agree with the others! The Mannlichen to Kleine-Scheidegg hike is my favorite hike in the Berner Oberland because of the glorious views, so if the weather is favorable, I'd recommend that one.
If you're thinking about going up to the Schilthorn, from Lauterbrunnen you can take the post bus to the Stechelberg lift station in order to take gondolas all the way up to the Schilhorn. Alternately, you could take a gondola from Lauterbrunnen up to Grütschalp, then take the train from Grütschalp to Mürren. From the Mürren train station it's about a ten-fifteen minute walk to the Mürren gondola station, where you could then catch the gondolas all the way up to the Schilthorn. I would only head up to the Schilthorn if the weather is nice.
On the way down from the Schilthorn, when you come back to Mürren via gondola, you could do the hour-and-a-half-ish, fairly level walk to Grütschalp and then take the gondola back down to Lauterbrunnen. Or, you could walk from Mürren down to Gimmelwald (Rick's favorite spot in the Berner Oberland; the walk down takes about 30-45 minutes), take the gondola from Gimmelwald down to the Stechelberg lift station, and then walk along the valley floor back to Lauterbrunnen (an hour to an hour-and-a-half walk).
If the weather isn't nice, personally I would take the gondola from Lauterbrunnen to Grütschalp, then take the train to Mürren (or walk, if you're up for more walking), then walk from Mürren to Gimmelwald, take the gondola from Gimmelwald to the Stechelberg lift station, and then walk the valley floor back to Lauterbrunnen. The valley floor walk is a good rainy day option. If it's socked in higher in the mountains, it's usually still really beautiful on the valley floor. Also, you could stop at the Trümmelbach falls en route.
These options can sound a little overwhelming before you get there, but once you're in the valley, it will make sense. Hope that helps! Have a great trip!
