Enjoying like u described seems a good idea, but its our first travelling at coastal highway till Gawadar and friends who traveled before us guided us not to travel after Evening / Night till Gawadar as its risky, so we have to keep this point in mind,
however, after our this journey i can say that its completely safe to travel at coastal highway anytime provided that your vehicle is dependable and you have plenty of food along - No local Dhabas / Hotels / Pakistani Petrol Pumps available from Hub till Gawadar only Irani Petrol n Balochi Brothers.