I agree with all of the above BUT I would also recommend getting to Bunji (assuming you do it on the way north) and then turning right towards Astore, then on to Skardu via the Deosai Plains National Park. After Skardu, you can do another little trip to Kaplu and then back to Skardu before rejoining the KKH just south of Gilgit.
While in Astore, there is a little 5KM side trip up to Rama Lake but I'd recommend you don't do it in a 4x4 unless you want to come 6 inches from dumping said 4x4 in the river when the track starts to collapse under the weight!
Skardu is an absolutely idyllic little town, with stunning mountain peaks and even beaches on the Indus river. While there, stay in the Dewan-e-Khas hotel. Around Skardu, there's Shigar and Satpara Lake while Kaplu is also well worth going to.....although we didn't quite make it there as we took a wrong turning to the south half-way there and ended up nearly at Kargil !
Writing this has made me wish I was there again.
Check out the pix - overlandcruiser.net