If you really, really are up for the whirlwind daytrip of a lifetime—the Basel to Lauterbrunnen to Lucerne to Basel train ride is it!
The approach from Basel to Interlaaken takes you past Thun, with its castle. Lake Thun is beautiful as is Lake Brienz. Change trains in the town between the lakes— Interlaaken— and in 22 minutes you’ll be in the Lauterbrunnen Valley. It’s a glacial-carved valley akin to Yosemite Valley in California, but with the Eiger, Monch and Jungfrau peaks towering above the valley. If you get a really early start, I highly recommend going up to Murren just to see the views of the Eiger, Monch and Jungfrau peaks across the Lauterbrunnen Valley. ( The views are so stunning that, armed with a Eurail Pass years ago, I once spontaneously jumped on a train from Frankfurt Germany just to see them again before continuing to the Netherlands. That was an incredibly long, but unforgettable daytrip)! There’s a Coop grocery store in Murren where you can get picnic supplies and take in the views outdoors. There also are hotel restaurants in Murren. With any extra time, the hike from Murren to the Stechelberg gondola is a flat, easy 45-minute hike with breathtaking views of the Eiger, Monch and Jungfrau 13,000+ feet high mountain peaks Take the Stechelberg gondola back down to the Lauterbrunnen Valley. A bus runs from the base of the Stechelberg gondola to the Lauterbrunnen train station a few miles away— maybe a 10-minute ride. You’ll likely see the 900-feet Staubbach waterfall while in transit.
Return to Interlaaken from Lauterbrunnen and transfer trains for one of my favorite Swiss train rides in the entire country— Interlaaken to Lucerne via the Brunig Pass. This train ride takes 2.5 hours and is incredibly beautiful. From late spring to early fall, the mountainsides are blanketed with the greenest grass and there are turquoise lakes below, all colored by the minerals of the mountain glaciers. Words can not describe the experience.
After arriving in Lucerne, just walk across the street from the train station and you’ll be in the “Altstadt,” or old city, of Lucerne in 5-10 minutes.
Walk around the Altstadt and see if you agree with so many others who think Lucerne is the most beautiful city in Switzerland.