Lucky you, living where you do. If I lived in a salt-free environment, we'd be doing the same thing. I think most any 1960s vintage car is easily suitable for every day use. By then, cooling systems could keep up, heaters were becoming standard and radical things like overhead valves were commonplace. It can be done with 1950s cars too, but I think they are a little more involving for both maintenance and keeping them pointed straight down the road. If one isn't picky, any number of 4 door sedans from any vintage can be picked up inexpensively, and if it's a common brand like a Ford or GM parts are never a problem. Sadly, I live in a place where they use salt at the first sign of a snowflake, so can't bear subjecting anything that has survived 50 or so years to a constant barrage of what equates to acid to it's metal parts. One local guy does drive his stuff year round (Buick Riviera, monster Pontiac Bonneville) but he does all his own painting and body repairs in his shop so doing an annual rust fix isn't a big deal to him.