You can cover Galiyaat and Kaghan Valley in 12 days.
Spend a week in Galiyaat region and then move on to Kaghan Valley for 4,5 days.
Couple of days in Murree.
Then move on to Nathia Gali and spend few days there.
Couple of days at Shogran, Sri Paye
Then 2,3 days in Naran.
If u don't want to go to Galiyaat then go to Kashmir and then Kaghan Valley.
Visit Banjosa Lake, Rawlakot, Toli Peer, Muzaffarabad, Pir Chinasi. Then onwards to Kaghan Valley.