Hey Shubee, Yes, it is completely safe to visit Kasol for girls. I have visited most of the Himachal and i noticed that people of Himachal are very kind and helpful to tourists. So go ahead and plan for your solo trip. This is my simple itinerary of Parvati Valley : https://www.tripoto.com/trip/covertheparvativalleyin7days-5bab66898dbe9?ref=mobwapp&source=awp Hope this would help you. Happy traveling!!