Did a road trip in sep last year all the way to China border in oriel prosmatic 07 but that's completely a different story.
As for khi-islo. well to describe the roads, the worst is khi-hyd after that its solid and reborn is so much fun.
Car Worry:
Well i hate to admit it but on your way you will notice that honda in general will be seen lesser and lesser and ratio of civic in particular will be at max 10:2 and there's a solid reason behind it, no matter what others say civic here is not made like corollas are which btw will be everywhere.
having said that khi-isloo is not a biggi for civic if its even vaguely maintained like mine, i had no issues what so ever so cant say much.
Time:
I left at 4am and cleared sindh before the sunset, recommended (i dont know why as rangers posts are more frequent now). i traveled all the way to lahore with just one stop at mc donald sahiwal and reached lahore around 12-1am. I could've traveled to isloo directly but decided to meet a few uni friends and stayed the night, from lahore via motor way its a piece of cake and a drive of 3-4 hours. just carry around 600 min in cash for the toll which was i guess was 570, this is important as all other toll will be 30rs if i remember correctly and there will be plenty of these so keep the change (30 for each city)
paperwork:
i had nothing as i left in super hurry at night around 4 am and was alone on eid vacations and decided to spend with extended family and all documents were at office and by nothing i mean no license (have uk license but was only carrying cash and a credit card) no car book or paper of any kind and was travelling alone till isloo where my wife joined me from her states trip.
Just keep the running paper, license, cnic and that will suffice.
Police:
got stopped only once somewhere in sindh by those typical half open shirt with huge belly trying to make a buck, just be confident if your stopped.
Multan:
there are two ways to go to lahore, take the one from outside the city as metro is being made inside and you will probably be stuck in traffic.
Mileage:
Mine was giving me 11.35 (kept a record of all filling so dead sure about it) and i was in no worry to save fuel so it can be higher if your responsible.
thats about it:)