Why is the Golgi Apparatus located where it is?
It has to be somewhere very close to the nucleus. The cell doesn't have a whole lot of other room in it.
The cell really has evolved over time and we may never know why the parts are where they are. It probably just the luck of the draw or chance.
The Golgi Complex basically functions as a "packaging center" for the cell, attaching "address labels" (functional groups) to various cell products to direct them to their respective locations, and "packaging" the products into vacuoles to ensure delivery.