Sorry, I am responding in place of Rehman Bhai ...
The most important thing is that your car should have good ground clearance, otherwise, you can expect your silencer to fall off somewhere, and/ or other damage. We have frequent land sliding in the north due to massive deforestation, so you should be prepared. It is good to have a complete set of tools, including towing rope and jumper cables in your car.
Somewhere in this thread, I mentioned Mustansar Hussain Tarar Saheb's "Safar shumaal kay" .. he traveled with his family in a Suzuki FX, and he did not mention any big issues. He traveled with his family.
You should also consider where you will keep your luggage. Using a roof carrier will obviously move the center of gravity much higher and also add lot of drag. So, you should think of the risks involved when you are driving on uneven roads.
