It would be ideal to cross the border further down by the coast and away from the specifically dangerous areas near the Afghan border.
I have heard of some people crossing in the south near Pishin - but it is not easy! The Pakistani authorities don't want you crossing the border in this area - I think they have some military stuff around there! There are alternative ways around, depending on where you want to get to. If you are heading to India, try the Oman route with a boat from Muscat to Mumbai, and if you want to do Pakistan, there is a route from Kashgar in China to Abbottabad (also one of the great roads/journeys of the world - the Karakoram Highway one of th ehighest paved roads in the world, I think!) - but this requires a journey over the top of Afghanistan, so Kazakhstan and Kyrgyzstan - I am planning to drive to India next year 2014, so have been studying options - the Iran Pakistan border is not safe and requires a police escort through to Quetta. Good luck with your trip.