Welcome to My Swiss Alps.
September is my favorite time to visit Switzeland.
You might like a bit of light reading about Wengen, which is an alternative to grindelwald with a somewhat different character:
The available routings can be found in the timetable:
The instructions are important if you are checking fares and ro get the most from the large amount of information available.
The timetable Defaults to the fastest route. You can force it through other routes by putting a location along the route in the "via" or "connections" box.
The ride over the Gotthard Pass via Flüelen is s particularly nice, but the fastest route goes through the new "basis" tunnel from Visp to Spiez after coming through the Simplon Tunnel via Domodossola.
The Gotthard Pass Route is 3 or more hours longer and really makes a very very long day.
A useful map is:
Under Points of Interest/Traffic you can turn on an overlay for various forms of public transport. Click on a station icon for an abbreviated schedule to/from that stop
Whether or not to purchase a pass and which one is described here:
There is a great variety of passes, and it can be confusing, so i always ask Arno or Annika, who are the system moderators and the experts on rail passes.