Very last minute, but I just noticed that there is a cow parade in Lauterbrunnen today between 12:00 and 13:00. They start at Hotel Silberhorn and walk through the village.
https://lauterbrunnen.swiss/de/entdecken/events/veranstaltungskalender.html
Wengen will have two groups Saturday Sept. 20. You can see the routes and times for that here, they will go right down to Lauterbrunnen:
https://www.myswitzerland.com/en-ch/experiences/events/alpabzug-wengernalp/