Both routes are right, Islamabad, Muzaffarabad, Ghari habbibullah, Balakot, Naran, Babusartop and Chilas. Depends upon if you want to travel on kkh or not, but here babusar top will be closed during this time of season.
Second option can be, Islamabad, Muzafarabad, Ghari habbibullah, Manshera, Bisham and so on to Chilas. Very long and not recommended if you intend to go via kkh.
Best option these days is Islamabad, Abbottabad Manshera, Bisham and so on to chilas.