The patch panels should be the same as those for a 1/2 ton. The cab corners can be found at any of the suppliers and the lower rear "B" pillar posts are also commonly available. Check ClassicParts.com.

Where are the holes in the bed located? On the sides, front panel? If the holes are located on a flat surface you can cut a patch from some similar gauge/thickness sheetmetal and weld it in place.

Is the roof a hole or a dent? If a dent it can be pulled out by welding a nail to the surface and "pulling" it out with a slide hammer. It might take some body filler to smooth out the minor issues left. If it is a hole then you can bend some sheetmetal to match the contour and weld it in place but be careful not to warp the metal as that area will not take too much heat at one time without bending out of shape.

If you do not have a welder you can rent them from some of the home improvement places.

good luck