I'm the guy going the other way to Sukkur. Let me add a couple of details:

1) If you want to visit Sindh province (e.g. Moenjo Dero near Larkana) you will be accompanied by an escort _all the time_. The ISI agency will not let you stay with any locals and will make sure that police always accompanies you wherever you go. Having said that the policemen will not mind hanging out with you but don't expect to have total freedom. If you meet up with locals (i met a few in Quetta and decided to pay them a visit in Larkana) the ISI will take their phone numbers, names, etc and i found that quite a few Pakistanis are freaked out by ISI (as one normally is by any other secret police).

2) Going north from Larkana along N-5 (the national highway linking Karachi to Peshawar) the escort left me at Sukkur. The N-5 is bad in Sindh and southern Punjab. Surface gets better in northern Punjab but the traffic is always terrible - countless bikes, trucks taking over all the time. Going is slow.

3) Motorway system is amazing - smooth, straight, flat (boring!) and with very limited traffic. Motorbikes are not allowed.

4) KKH (N-35) from Hassan Abdal to Mansehra is a good surface road but rather crowded so the going is slow (especially through Haripur, Abbotabad and Mansehra). An escort picked me up at Mansehra and we followed the KKH to Besham. Road surface is very good but the road is understandably curvy. ALtogether Islamabad to Besham can be done in a long half day.

5) 200km between Besham (we stayed at Midway Hotel for $6 per night) and Chilas took 7h. The first 60km is same good surface as the day before, then there is a 80km stretch of horrible road - extremely potholed, covered in landslides (on the way up to China we spent extra hour waiting because landslides came down a few hours before; fortunately they were removed). Then the rest is an ok surface. In Chilas you have to go to a police station, they take your details and a photo.

6) Chilas to Gilgit - the first 50km the road is not good but the rest is a fantastic Chinese built road. The escort will leave you somewhere between Chilas and Gilgit. Halfway through there is Raikhot bridge which is a base to get to Fairy Meadows - a beautiful lake with a magnificent view on Nanga Parbat. They won't let you drive up the mountain yourself but you will have to leave the vehicle and rent a jeep (for 5000-8000 rupies). The 12km mountain road takes 3h and then there is a simple 5km trek that takes another 3h.

7) Nanga Parbat is visible from KKH a little further on.

8) Hunza is amazing an everyone should go there. This is probably most liberal part of Pakistan and one of the more educated one as well. A lot of people speak English. Karimabad has some fantastic views. Somewhere between Gilgit and Hunza there is an area with a pro-Iranian Shia majority and they painted 'Down with Israel' and 'Down with America' slogans on the road with flags and all. An excellent photo opportunity.

9) 12km north of Sost on KKH at a checkpoint there is a Snow Leopard in a cage. The police guys feed it 3kg of meat every day and it's been there for the last 6 years. It looks miserable but it is still a magnificent cat. Don't miss it!

10) The NOC letter requirement for Swat Valley has been lifted as of the beginning of April 2015. We had to make the police at the checkpoint in Besham call their superiors to confirm but they let us through. With an escort of course. Swat is amazing - lush and green with snow capped mountains - looks very different from Hunza and it does feel like Switzerland of the East. Although with most population being Pashtun and strong Afghan influences the vibe is definitely more conservative.

11) In Swat the roads are good up to village Bahrain and the last 30km to Kalam (with lakes, mountians and meadows) is ungraded dirt road that takes 3h. There are tons of Buddhist remains, Madyan and Malam Jaba mountian resorts outside of Kalam with spectacular views. We couldn't shake off escorts so i'm not sure whether it would be possible to hike in the mountains around Kalam.