I used to go to grindelwald a lot in summer hiking, not been for a few years, but I always dream of getting last train to kleine scheidegg (to avoid masses of walkers) ride up to eigergletscher and follow eiger trail singketrack all way back to brandalm I think it was.
Other one I thought about was bike up on gondola to first, hike a bike all way over faulhorn, then continue to schynigge platte and find a gnarly steep trail down to wilderswill.
Mainlichen to Wengen and down to lauterbrunnen?
Hmm I want to go back now and find some trails! Love that place especially onkel tom’s pizzeria!
Let me know if you ride any of above, may be utter rubbish mind!