Day 1: Take a bus from Delhi ISBT to Bhunter (Himachal Pradesh). You will reach Bhunter in around 12 hrs
Day 2: After reaching Bhunter take a bus for Kasol (Buses leave Bhunter bus stand every half hour). Explore the places around Kasol (the restaurants, Parvati river and villages nearby (Challal and Katargala)). Stay overnight at Kasol (Various accommodations ranging from 400-1500)
Day 3: Take a bus from Kasol (5:30 or 7:30 a.m) for Barsheni. It is an hour and a half journey to Barsheni. From there you can start the Kheerganga trek which passes through Nakhtaan village, Rudranag and an alpine forest. Trek can take anywhere between 5-6 hours. Stay at Kheerganga for the night. Beautiful view of stars and hot springs are the attractions.
Day 4: Take a hike back from Kheerganga, which will take 3-4 hours. Explore nearby villages near Barsheni (Kalga, Pulga)
Day 5: Return from Barsheni and visit Manikaran and other villas near Kasol or explore areas near Kullu. A bus leaves Barsheni every 1 hour for Bhunter (9 kms from Kullu). Return from Kullu or Bhunter to Delhi