Bro thanks for this. For your upcoming plan 3 days are too short for the trip because
From Lahore to Abbotabad - 6hr
Abbotababad to Chillas 10-12 hrs
Chillas to Astore 5-6 hrs
Astore to Deosai: 6-7 Hrs
So in 3 days you have 72 hrs approx. and one side travel in ideal condition will take 30-32 hrs.
You will better calculate the rest.
One more thing there is no space to stay at Deosai so you have to plan day trip to Deosai
I'll advise you to increase the no of day in order to enjoy the beauty.