Depending on where you live, I personally have had the best luck in scouting remote areas within a couple hundred miles from my house. It amazes me what is out there, in scrap piles, behind barns, in barns, tucked away, etc. etc. Along the way I have bumped into the people who don’t want to tell you what’s in the barn or located just below that hill, but these are a small percentage. As long as you approach people with a level of respect and honesty and let them know what you are trying to do. In fact take some photos so they too can see what you are attempting to build. Since you indicate you have welding experience you will have a much easier time rescuing those "Abandoned" old rods than you will a family's pride and joy car which is tucked neatly away. Good luck and have fun, the hunt and the people we meet is the most pleasurable experience, and the vehicle is just the cherry on top!