Can you jack that thing up or crawl under there and take diagnonal measurements on the frame? A big come-along might be all you need.
While you're under there check to make sure the front and rear axle mounts are still fastened to the frame.
You may need to straighten the frame and then weld the brackets back in the right place. There's not much money involved unless you have to hire it done. I have done one like that.