I was told by the GSP you can ride with the doors off as long as there is a "lip". The floor pan cannot be even with opening. This is to keep things from rolling out on the road. As far as the mirrors go:
§ 40-8-72. Mirrors
Every motor vehicle which is so constructed or loaded as to obstruct the driver's view to the rear thereof from the driver's position shall be equipped with a mirror so located as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of such vehicle.
While it is legal to drive without side mirrors, a couple policemen told me if I mount side mirrors that most of them wouldn't even bother looking for anything else. I try not to give them a reason to want to pull me over. As you well know, the less attention you draw to yourself the better. Esp if you're driving in Cobb County.