Jan 19, 2011 - 2:41 PM
With a Swiss Saver Pass, the ride is for free up to Wengen/Grindelwald. From there, a 25% discount applies, so you have to purchase 25% discounted tickets. This can be done at a railway station, for example at Interlaken Ost (from where the trains in this direction leave). You don't have to book your tickets in advance, you can simply by them at the spot right before boarding the train. In most cases, there will be enough time to switch trains. The timetable I mentioned before shows how much time there's available for a change of trains.
The Swiss Saver Pass allows free travelling in regular trains, but no guaranteed seats. However, this won't be a problem. It's not necessary to make seat reservations, as enough seats are available in most cases. For many trains seat reservation isn't even possible. Only in rush hours it may be crowded on some routes, but this can't be prevented. As you'll be travelling in June, you won't have to deal with the tourist high season.