Sep 17, 2016 - 6:29 PM
Hi ayvid, welcome to MySwissAlps!
You can buy bus tickets from machines or staffed ticket desks at train stations (e.g. Interlaken West). Sometimes the driver sells them too, but don't count on that. Buying in advance is in any case more convenient than in the bus.
As for your other questions:
Day 2 a) Regardless of your pass you'd take the cableway to Wengen, then trains to Interlaken. Or, you take the gondola to Grindelwald Grund and trains to Interlaken from there. Schedules are in the timetable.
Day 2 b) That should work, except in winter when it gets dark early.
1) See the timetable please, and the Jungfraujoch page.
2) The page lists many tickets. Just go to the station, show your pass, and buy your return tickets to Jungfraujoch (up via Lauterbrunnen, down via Grindelwald). You'll get a 25% discount because you have a Eurail Pass. You can buy the First tickets on the spot in Grindelwald.
Last modified on Sep 17, 2016 - 6:31 PM by Arno