3 days in late Sept. staying at Esters Guesthouse. Advice on best highlights?
Gimmelwald is beautiful but really tiny. You'll need to go up to Murren for a Coop grocery store and restaurants. Of course, there's much to do in the surrounding area. Maybe review a guidebook for high lites and let us know what interests you, as Everyone has a different definition of "best". Safe travels.
Staying in Gimmelwald is a good opportunity to relax and do some touring on that side of the valley. You might enjoy having a "cool one" on the patio of the Pension or at the Mountain Hostel, and just enjoy the spectacular views. You could also spend a few hours having a look around Mürren and of course take the cable cars to the Schilthorn.
The Allmendhubel funicular should still be operating at that time, so you could also take the funicular to the top, and then hike back to Mürren through the alpine meadows (it's not difficult).
You might have a look at the current RS Switzerland guidebook for other suggestions. If you're going to be using the lifts frequently in that area, one of the Swiss passes may save you some money - https://www.ricksteves.com/travel-tips/transportation/trains/switzerland-rail-passes .
As I recall, it can get a bit chilly at night at that time of year so be sure to take some clothing for "layering".
The Gimmelwald website has lots of useful information:
https://gimmelwald.ch/?lang=en
Maps here of Gimmelwald and nearby Murren:
https://gimmelwald.ch/?page_id=1083&lang=en#038;lang=en
Hiking:
https://gimmelwald.ch/?page_id=83&lang=en#038;lang=en
Some of my best and favorite pictures are from the walk from Murren to Gimmelwald.
I’m pretty sure that Pension Gimmelwald mentioned by Ken is where we stopped for lunch. We sat outside, eating our sandwiches, enjoying the view and watching the paragliders.