Larry, the fact that Squarebirds are rare in your part of the country might be the very reason why you might want to own one. Once restored to good working and looking condition, it should certainly attract a lot of good attention. As for parts availability for these squarebirds, there are a lot of parts available. We have numerous major Tbird parts houses that have parts for them. We have several companies who have parts cars they can pull parts from, or have already pulled the parts and stocked them. The Bird Nest in Oregon, the Bird House in Delaware, and John Draxler of the Thunderbird Ranch are three that come to mind. You can find all the Tbird vendors listed down in the Advertisements Forum. Their contact information will be there.
If you buy a Tbird, you will want to buy a shop manual for it. Ask the owner if he has one that will come with the car, plus any other repair manuals he might have. If he doesn't have them, you can get them from the parts houses. If you buy, contact all of them and ask them for their free catalogs. It will let you know what is available in the way of parts, and with them you can comparison price shop.
As for the '58 and the '59, if they are junkers, not to be restored, grab one of them as a parts car. The parts for all three squarebird years will work on either one of the three years, for the most part. Please do me a favor, and ask the owner to give you the VIN #'s and the Data Plate information off all three Tbirds. Or take pictures of them, if he will allow it. We are trying to get the location and existence of every remaining Tbird into the Thunderbird Registry by fellow member, John Rotella, who runs it. www.tbirdregistry.com
His goal is to account for every remaining one, including those that have been crushed, parted out or still running.