Assalam Alaikum.
My apologies for the delayed response. I didn't receive any email alert about your comment and thanks to another PW friend who informed me.
Recently, on 28th September 2014 I did Karachi ~ Islamabad on Honda Civic 2002 VTI Prosmatec with my friends. The road in Sindh is under-construction, however it is clear once you enter Punjab.
You may spend night at Sadiqabad or Bahawalpur. Internet maybe used for hotel search, however, I suggest you should check and bargain various hotels you will find in the two cities. You may also stay at Bahawalpur Cantonment.
The route is clear: Karachi ~ Hyderabad ~ Moro ~ Sukkur ~ Daherki ~ Sadiqabad ~ Lodhran ~ Khanewal ~ Kachcha Khoo ~ Abdul Hakim Cantonment ~ Pir Mahal ~ Toba ~ Faisalabad ~ M3 ~ M2 North ~ Islamabad and you can do it without Google maps
Now we keep home cooked food, drinking water, biscuits / chips and fruit when traveling on road. Mrs. RZ stores bread and spreads for instant sandwiches for kids. I have also added a battery operated air compressor to my tools, though never used so far
I wish you all the best with your tour and expect a detailed thread on PW