Kheerganga is a two day trek, with first day of ascent and overnight stay at the peak and one day for descent.
Depending on the no. of days available, you can plan for Kasol, Tosh and Manikaran too along with Kheerganga! With sincere hopes that the trekking realms get opened soon for all of us! :)
Kheerganga trek starts from barsheni. You'll have to take a taxi or bus from Bhuntar to reach there. kheerganga is a 2 day trek. You could also visit Kasol, Manikaran, Tosh and maybe Manali of you have a week in hand.