I also did a 11 day trip to gilgit, hunza & Astore valley, Skardu and Deosai plans on my 09 Altis. Road is overall very good. We were 4 with luggage in the trunk. We started our journey from lahore, took motorway till burhan interchange, then switch to hassan abdal, and reached abbatabad and mansehra. From mansehra we have to choose 1 route out of two. One was continue on Karakoram highway and second was to go from naran side. We chosed karakoram highway. Road was quite good but when we reached Kohistan, road turned into its worst condition. It took us 5 hours to cross that 75 kms patch. Then after reaching Chillas, again road was amazing and also suitable for night driving. We reached gilgit at 11 pm after a journey of 22 hours.
On the way back to lahore from gilgit, we choose babu sir top and naran's route, that is very good as compared to the previous route.
So I recommend you to choose Babu sar top route having night stay in Naran if you choose to start travelling early morning. Also do not try to go in Deosai plans on your own car. Go Skardu via Karakoram highway from gilgit. And then hire a local jeep for deosai. And if you choose to cross Deosai plans from Astore, then Chillum is the last point where you could go in ur own car. Ultimately you have to hire a jeep for deosai plans.
If Deosai plans and Skardu is not in your trip then please add these places to you trip.