where are you leaving from? Karachi?
Roads - they are all good. relied majorly on Google Maps. Download maps offline as well just incase, although the network works without any issues. I faced issues as i approached Naran.
Sim - Jazz/Warid/Ufone coverage is not that good i heard. As i had Jazz, i bought zong sim with data package which i used for navigation with traffic updates
Petrol - prefer to get petrol within city (like as you enter swat compared to N/M roads. I kept extra can just for peace of mind, but didnt really needed it
Services - Services (rest rooms) in punjab are far better compared to sindh. in sindh i used the ones on M9 and then at McDonald @ PanoAqil* location (i guess)
Stopover - plan your visits ahead of time. with family and kids, i decided not to drive after maghrib at all, and left early accordingly. biggest challenge was as you leave khi, so it takes 14 hours (with 1 hr stopping time) to reach Bhawalpur. Stay in Sadiqabad would be relatively early compared to BWP. I had my wife driving as well so we were switching, but its easily possible if single driver - provided you can stay awake
Car & Documents - kept original CNIC/License/Registration Book/Insurance paper just incase. however no one asked anywhere, as travelling with family. better to keep air filter, plugs etc depending on car condition. I just changed oil, filter etc before leaving khi....didnt needed to go for oil change in middle but soon after returning (4400 kms done, oil change was on 5000 kms).
get smart tag as it really eases travelling on M1 and M2. load of 1500 would be more than enough and you will still be left with balance.....
Let me know if you have any specific questions, and will try to answer.