2 days trip - Chill in old Manali, can visit Rohtang pass.
3-4 days - Kulu or Shimla can be added
5-6 days - Better Strech for 7 days and do a Spiti Valley trip. Very worthy.
Hi Kishan, Attached below with my comments are few packages for hassle free travelling. You can take a look, fill the form and someone will get in touch with you. Thanks!