We did this tour twice, first time two days, with the difference that we turned left already at the remains of the barracks (Za lepočami) (I don't know why it only says planina Razor there, because in five minutes you reach the Krn sign on the right). This way you lose less altitude and save a little ascent. And you see quite a bit of history, if the weather is nice, remains of the hospital at Prehodci, Batognica. It is really a nice tour and can be very hot, we felt it last year, when from Savica to Krn it was sunny all the way and the steep ascent over scree to the marker was really "hellish", luckily we were up before noon. And as you wrote, because of the distance it's for a day for exceptionally fit ones, when you look from Bogatinsko sedlo back towards Krn, the summit seems so far ...