The three aren't usually covered in a trip at once. You should make a trip to kinnaur valley and explore it fully. Here is a proposed itinerary Day:1 Start from Delhi and cover till Narknanda Day:2 On the second day, Narknanda to Sangla Day:3 On Day three, visit Chitkul and Kamru Fort during the day and come back to Sangla. Day:4 Day four begins with you embarking for Kalpa. Walk up to Roghi Village (although only open during the summers) and get back to Kalpa to end your day. Day:5 Leave for Sarahan. halt at Sarahan if you want to otherwise continue to Narknanda or Fagu. Day:6 Leave for Delhi from Narknanda early in the morning as this is a very long drive.

You can find the details of the places to visit and things to do here- http://www.holidify.com/places/kinnaur/

You can find the details of the places to visit and things to do around Kinnaur here- http://www.holidify.com/places/kinnaur/