Like any other project, you start from the bottem and work your way up. You can have a beutiful body but, if the frame ain't no good, your body won't last long.
First, if the body is half off, half of your work is done. Take it the rest of the way off and take care of the frame. While the body is off, clean and repair the bottem of the body, redo any wiring that needs attention ( replace battery cables), replace any insulation and heat shielding that is missing. After this is done and the frame is ready, with motor, trans, exhaust, gas tank, shifter, etc is on the frame, set the body back on it and start doing body work, keep in mind to cover all prevoius work........Hope this helps ya a little.........Steve