all 4 points above have zero gravity.
I have my 2 Karachi registered vehicles in Islamabad. both travel as far as upto Kalam & Kaghan and visiting Karachi in mild weather in 18 hours is very convenient, so far we know 3 mandatory stop points for police check when travelling down south in selective religious months only.
tax payment - yes that is an issue for people who do not have friends families else no issues.
RUST ??? - Tube well water 'WATER BATH (servicing) create equal rust' in 1 year as a car in Karachi in 2 km proximity area of beaches.