5 days may be too much to visit in Kasol. Kheerganga - This may take your entire day for trekking, Trek from Kalga. Do an overnight camping
Tosh - Trek to Tosh and enjoy the view from Pink Flyod cafe.
Manikaran - Hot springs.
Kasol - Street walking and shopping, You can go for some cafe - Jim Morrison Cafe. You can stay at Nomad hostels or any other homestays/Shacks around.
Few of the must do things you have already mentioned a trek to Kheerganga, Malana and Tosh. Beside you can take a walk beside Parvathi River and can taste some awesome Israeli Cuisine at Turquiose Kasol and The Evergreen. You should not miss Street shopping and Rice beer and post all your trekking once you are back to the town sit and relax at Moon dance cafe and cherish your memorable experience.
Since you have only 5 days, start each day early in the morning. You can cover Kasol in few hours by exploring the market and some cafes. Trek to Rasol and spend a night in Rasol instead of staying in Kasol, Choj or Chalal. Explore Chalal on the way to Rasol. Move directly to Tosh and you can stop at Manikaran on the way from Kasol to Tosh. You have to trek back till Kasol market from Rasol and you can get shared cabs from Kasol market. Stay in boom Shiva cafe or pinky didi cafe for a night in Tosh. My recommendation would be to go to Kalga and Pulga instead of Kheerganga trek. Kalga and Pulga are more beautiful compared to Kheerganga. Stay for one night at Kalga and Pulga. If you still have the energy and time you can visit Tulga also.
Still my suggestion is to extend your trip by some more days and cherish the beauty of hills with no hurry.
At kasol explore the local market and stay at reverside camps at chuj (this place is at walking distance from kasol main market)
you can also spent time in Jim Morrison kafe in kasol.
on next day trek kheerganga and spend night in camps .
on day 3 , as you return from kheerganga head to Tosh . and take rest in cafes like shiva cafe , pink Floyd cafe . on day 4 while returning from Tosh , visit Manikaran hot water springs .
If you traveling via Delhi, then Day 1 : Arival at kasol.. after check in take some healthy breakfast at Evergreen Cafe then go to Rasol.. Day 2 & 3 : Take bus or share taxi to Barseni for Kheerganga via Manikaran ( 2 days for Kheerganga) Day 4 : Return to Barseni and go for Tosh or Pulga
Day 5 : Take Share Taxi or Bus to return Kasol, in evening take your dinner at Moon Dance Cafe Next day back to Bhuntar to return Delhi.. Be a Responsible Traveller 👍🗺️