Brother, I had similar questions in April this year prior to my KHI-ISB trip.
Believe me you will find many options along the route.
I left KHI Clifton at 8am on Sat morning, less traffic on road and many hotels, restaurants on the way.
Our first stop was near sukkur at Royal Taj, next stop was at motorway rest rest area and another one at pindi bhattiyan
Family of 5 and Alhamdulillah no issues at all driving all the way from KHI to ISB in one stretch.
NH-5 be careful with bikes, rickshaws and trucks
Motorway is quite, smooth and a bit boring