Day 1. Leave Rawalpindi
Day 2. Arrive Gilgit / Overnight Stay
Day 3. Drive to Phandar Valley, explore surroundings and Phandar lake, overnight stay.
Day 4. Drive to Hunza, enroute sightseeing, stay at Minapin, Diran guest house.
Day 5. Explore Karimabad Hunza, drive to Attabad Lake view, tunnel crossing, back to Hunza, Duikar, stay at Eagle Nest Hotel.
Day 6. Drive back to Gilgit, then Islamabad.
Day 7. Home Sweet Home.
You can skip stay Diran Guest House and go straight to Eagle Nest at Duikar, views from there are stunning! I just added Diran for change. 
If you really want to explore Skardu, then bad news is Deosai Plains will be close at that time, possible plan for Skardu may be;
Day 1. Leave Rawalpindi.
Day 2. Reach Skardu.
Day 3. Visit Katpana Desert (Cold desert), continue to shigar, over night stay at shigar.
Day 4. Full day Deosai Plain visit if open.
Day 5. Visit Lower Kachura (Shangrilla), and easy trek to Upper Kachura Lakes, back to Skardu.
Day 6. Leave Skardu for Islamabad.
Day 7. Home Sweet Home.