It is between a 7 to 11 hour drive depending on the average speed you can maintain and the number of pit stops you make. Ideally you should do this in a group of vehicles so that if one of you breaks down there are a few handfuls of help around.
Petrol is in short supply though diesel is available at varying prices and quality. You may need to carry a jerry can with spare fuel for part of the trip.
You also need to carry your own food and water from here to Gwadar and back. Rest areas with bathrooms are in even more short supply. What goes in must come out. Stay away from caffeinated drinks and heavy food.
If you can afford it, stay at the PC, there aren’t any major surprises there. But there is no swimming pool and only Nadia coffee shop is open for service.
Ask the folks at PC to turn the hot water on in your room. If you don’t there is a small chance that you will only get cold water in the taps and showers.
Jet skiing is fun in a mid to large size group and you won’t do more than 15-30 minutes each. With a smaller group you may not have as much fun.
The Makran Coastal highway touches the sea only at a few locations (Kund Malir, Ormarah and some parts of Hingol National Park), the rest of the drive is wide open barren plains and mountain ranges.
If you are looking for a shorter drive you can still do Kund Malir (241 Kilometers from Karachi) and Hingol National Park (immediately thereafter) in a day and be back. Pit stops though would be an issue.