The problem is finding "old" salvage yards that didn't crush tons of older cars when scrap prices spike. Old Cars Weekly often runs articles on salvage yards with vintage cars. I struggled with their search engine to find a past article, but it might be worth a look there.
Otherwise, WI, MI, MN, MO, AR, KS, OH & CO are the only states with bone yards I've known of them being in the past.
Thanks for input. I know that there are several semi-active yards in Maine but their information is not readily available. There are a few yards still here in western Mass, but they have none. I know that there a several big, well advertised yards in the upper mid-west with Aeros but the dismantling and shipping costs are just too high.