Grand Hotel Giessbach. Above the Brienzersee. Hike, waterfall, boating, good food. It made for a very pleasant visit.
I don't know if it's a secret place but it's one of the more memorable that Ive been too and I rarely hear it talked about or recommended. I seem to recall it took some effort so maybe its off the typical tourist path.
Something even more off the beaten path in that area is Hotel Rosenlaui.
It isn’t for everyone and we will never ever stay there again, but I’m still glad we went. The hotel is a time capsule from the Belle Epoque period and they want to keep it that way - they also do not allow photos or any jovial behavior + your room may be haunted, even if you didn’t believe in ghosts prior to staying there. I hope our ghost was Tolstoy or Nietszche, who both stayed there.
If all the above sounds like too much, you can drop in for a drink or lunch to see the place and continue on a very beautiful hike.
Replying to my own post for anyone who might find it useful… we did the Val Bavona hike described in the Guardian article during the Pfingsten/Pentecôte weekend, and it was fantastic. The most surprising thing was the lack of tourists, maybe put off by the weather forecast, but we had sun all the time, including the previous day when we hiked from Someo to Bignasco.
Allow 5 hours from Bignasco to San Carlo to take in all the scenery without rushing, plus an hour or two for beers at the Ristorante Basodino in San Carlo while waiting for the bus back down the valley. Paradise.