By Train/Gondola/Foot
Catch the Lauterbrunnen-bound train from the Interlaken Ost Station, and get off at Lauterbrunnen. Make sure you board the correct car, the back few cars go to Grindelwald. Eurail/Inter-rail passes are only valid for a discount on this line, so be sure you have an actual ticket before boarding the train. You can buy a ticket valid all the way to Gimmelwald, with the PostBus (http://www.postbus.ch/en/...) and gondola fare for the second leg of the journey included.
At Lauterbrunnen, cross the street and board the yellow PostBus heading for the Stechelberg gondola station, and get off there alternatively, it is possible to drive and park in Stechelberg.
Ride the gondola up one station to Gimmelwald. Alternatively, you can take a 1.5 hour hike up to Gimmelwald from Stechelberg and save money on the gondola fare.
