By car, and only by car. Parking depends on season and time of the day. At Jasna finding a spot is easier then at Vršič Pass, yet with a bit of luck and patience you will get a spot at all locations.
Thanks for your answer. And how can we do them one by one? I mean start from kranjska gora and then lake jasna and trenta valley or other way round?
Where are you going afterwards? If you are returning to KG, consider taking the other pass (Predil) on the way back. This means following the road to Log pod Mangartom instead of back to Trenta when you head north from Bovec.
We are currently staying at a location overlooking Lake Jasna and Road 206.
We took this drive today and started at the Kranjska Gora end and drove to Bovec. We found ample parking at all spots along the route and found the drive to be very nice. We stopped about 10 times so the drive took us about 2.5 hours.
After spending a short time in Bovec, we retraced our route back to the hotel at Lake Jasna. We are glad we did this since we did get to see the route from a different vantage point.Edited: 07 July 2018, 21:24