I was in a valley in the Alps (Alagna, IT) very close to Switzerland, but the road ends there. The Tesla website would suggest DeCs in Switzerland, but those were actually 3~4h driving as I had to navigate through the mountains.
The Tesla website on Mobile (iPhone) doesn't show a map, you only get back a list. I eventually used Google Maps and searched for "tesla destination charger" and found a hotel which suited me.