Living in Northern Wisc. I can relate to availability here. You might want to look at the Dakotas or Montana. More rust free stuff out west.I have the name of a fellow in Montana that sells rust free parts and cars I can send you his info if you want. I think you have a good grip on what you want and what you want to pay. If more folks were like you the prices wouldn't be so high. I can't find anything here that is not a total rust bucket for $4,000. I have some c-bodies to keep me happy for now but would like to get back into a 69 Dodge b-body. Gonna be a long wait.
Any way you keep it up and let us know what you find.