Replacing major rust-out between the rear fender and door of the 1947-1955 Suburban or panel truck can be easier than you think. The curvature in this area is the same shape as the adjacent door.
Therefore, locate a 1947-1955 donor door of limited value due to butchered radio speaker holes or a badly rusted bottom. Remove the outer panel. It has the correct metal gauge and round shape as the Suburban and panel truck body.