While I can't answer your specific question because I was there in May, I can tell you that the Sound of Music is not a very big deal to the average Austrian and from what I can tell, not many people know about the trail. When we walked it in May we saw about four or five locals using the trail for fitness and walking their dogs. We were the only ones to go there for the trail itself and spent an hour at the park at the top with it all to ourselves. BTW, there is parking on the main street with a three hour limit. I think that it was one euro per hour. We parked across from the visitor's center, walked a few doors down to the supermarket and went to the back and had them make a sandwich for us, and we went to the top with a picnic. The visitor's center closed in the middle of the day for lunch when we were there.