what part of the body makes the most sense to start on

Get your doors lined up and shutting nice before you remove the quarters. That way you know the doors fit and are lined up before hand. Use the doors as a guidline for installing the quarters. Then you can remove the doors after the quarters are on. I have seen idiots dismantle a car and install new sheet metal only later find out nothing lines up afterwards.

good idea,...I thought about doing my trunk pan first cause I gotta do this before I replace the tank,...but the doors first makes more sense.