What is meant is the route from Alp Astras to the Pass da Costainas. This does not take place in Switzerland (in contrast to the first comment here). National Park (bicycles are not allowed there), but close to the park, on Swiss territory.

Beautiful trail in an idyllic landscape to the Pass da Costainas.

A great landscape. That is beautiful. Everyone is just passing through here and so you meet very few people.