Some trekking companies take 10 days to do this trek, we did it by ourselves (only getting lost once!) and managed it very easily in five and with two rest days!
Our version of the trek involved:
Day 1: Kasol to Rashol- 2-3 hour steep climb
Day 2: Rest day and a small walk to the top of the ridge near Rashol
Day 3: Rashol to Malana over Rashol Pass 3180m (7 hours walk)
Day 4: Rest day in Malana
Day 5: Malana to Naggar over Chandrakhani Pass 3600m (9.5 hours walk)
All the steep climbs were worth it, all offering amazing views.