We arrive in Geneva around 9:45am. Is it too much to plan on going from the Geneva airport directly to Montreax, catching the Golden Pass train and arriving in Muerren in the evening? We will stay in Muerren for three nights starting the 18th of May. We are praying to all the weather gods for beautiful weather.
It looks like a 5.0hr-6.0hr. trip. You can catch the Golden Pass train in Geneva and take it to Interlaken Ost. You'll change trains a few times on the way but you'll see the best views of the run. At Interlaken Ost, you walk over to track 2A and take the 20 minute train ride into Lauterbrunnen. Make sure that you are in the carriage that says Lauterbrunnen. The ones that say Grindelwald separate off midway and go to Grindelwald.
At Lauterbrunnen, walk across the street to the Lauterbrunnen BLM (gondola station). I think that there is an underground tunnel also. It's only about 300 feet away from the train tracks. The gondola will will take you to Grutshalp where you change to a cog train for the remaining short ride into Muerren. Don't fret. It's all really easy.
Note that Muerren can be a bit quiet in mid-May. Some places may still be closed for Shoulder Season. During late April and up until late May, most places in the valley close as they transition to summer from ski season. We were there 2 years ago on June 1 and the weather was just great. No snow. But, this varies from year to year.
CLICK HERE for the Golden Pass website.