Check my gallery and you can kinda see what I did for wood hauling. No plans, I just figured it out as I went.
Racks are in 3 pieces, headache rack, 2 side racks and bolt together with 4 bolts.
I also have another board that bolts to the top of the back for hauling stuff on top, like my 15' coleman canoe.
All side rack uprights are shaved to fit in stake pockets, thing squeaks bad until there is a load in the bed but works well. I have hauled sliding doors, firewood, furniture and misc. other stuff with them since I built 'em 10 years ago.
I did get some special back plates that the bolts tighten into and grip the wood from the inside, should be available at any hardware store.

Good luck

Rich