First question i gotta ask is why wasnt the load tied down?
Make sure the cab itself didnt suck in at the corners do the doors still line up with the cab corner edge where it wraps around to become the back of the cab?
See if the roof has waves or bends in it. Thats a pretty hard hit.
You can remove the bed drill a couple of holes and strap some 4x4 on the inside and have a come along to pull the damage back out.
Put some chains through the top hole come down to the bottom hole 4x4 between the cab and the chain loop on the inside of the cab
Take two come alongs and place them at the rear of the truck frame and then start tightening them slowly.
just a idea. I dont think youll get it perfectly straight but it shoudl get you close. you can always use a hammer and block to do final stuff.
My buddy works for a body shop and hes here and we were looking at your truck and we thought this up. he said htats what he would do. hes gonna look at his shop ( not sure if you wanna pay the shipping. he said he has a whole pile of cut off parts in the back of the shop. he said you can have it if he has one. They throw the stuff out every month.
Bottom of window
Hole Hole
4x4----------------------------4x4
4x4----------------------------4x4
Hole Hole
Bottom of cab