Just returned from a Gwadar Trip, so feeling excited!
Last CNG station is at HUB, no CNG after that.
There is only one petrol pump that supplies Pakistani Petrol and that too is in Gwadar. But one can refill at Windar, 50 km from Hub, and 30 km before Makran Coastal Highway zero point. Provided one maintains reasonable speed and uses AC sparingly, CNG+one tank full should be enough for the trip...
Tyre shops can be found after every 50-100
And there are no Balochistan related security issues as such.
Hope this helps...