Hello,
I went there twice, first time with friends in August and second time with family in March.
No issue in going alone when you are with friends as far as your vehicle is in good condition, just make sure it is perfect in all aspects before leaving. Do carry some extra petrol in a can. At least 10 litres if going till Kund Malir and 20 litres if u r going till Ormara. Taking food from Karachi is a good idea, as the food available at Dhaba is expensive and not good, we took with us TIN PACK food.
It was extremely hot in August. If it is sunny the heat is unbearable in day time. However, it becomes easier as the day passes after 3 p.m. Consider staying a night at Kund Malir beach as u r going with friends, it is worth staying, the sunrise on the beach is treat to watch and the weather in summer is very pleasant during the night.
Recommendations given by @arsalaanali89 are really helpful, do consider them.