Dear ame_raz, route map was quite simple. We use GT road for travelling from Lahore to Rawalpindi/Murree. Then from Murree, we use kohala road to travel to muzaffarabad [this road goes through Gharial camp, bhurban, kohala bridge (neelum view point) and straight to muzaffarabad]. Very scenic road.
We used rented hi-roof for the trip, and could not able to properly monitor mileage from home to home but petrol consumption from home to home was around 14k-15k.
Road from Kundal Shahi to Kutton was not as good but also not as long, some 3-4 km i think, so that's why you can take your car there.
Road condition is fine till Keran. But from Keran onward, road condition is not so good and a lot of water streams are there on the way with bad patches... therefore, i will not recommend city car from Keran onward.
Weather at day time of our visit was somehow hot at Kutton, but pleasant at Sharda and Upper Neelum. Nights were chill.