Don't know about cultus but from Kamalia to Islamabad one way Petrol is about 2700 PKR ( on Swift 2014 average speed 140 )
Kamalia to Multan ( Two way ) is about 2000 PKR ( on Swift 2014 average speed 120 )
i mostly go Islamabad from Faisalabad -> Pindi bhatiiya.. and most go Multan from chichaWatni -> Mianchannu -> khanewall.
now you can use this way. Islamabad -> M2 -> Faisalabad M3 -> Samundari -> Rajana (Turn Kamlia Road ) -> Kamlia -> ChichaWatni ( turn Multan road ) -> KhaneWall -> Multan
only 35 to 45 KM ( Samundri to Rajana ) road is Average. Rest all from Islamabad to Multan ( the way i told ) is Carpet Road. not a single jump on them...
Rest you can Calculate estimated cost on your cultus...
Br
Faisal_Computer