Ditto, a solid older vehicle is a cheap ride in the long run.
For the AC, I fixed my 91 Lincoln about ten years ago with a similar problem. The diagnosis was the compressor. So I bought the long line which included the drier, plus an aftermarket compressor, for about $250 total. My shop I've dealt with many times before. I brought him the parts and two cans of R12, so he recovered the old freon(was about half full), and I replaced the parts in his parking lot. It took me about two hours to do the parts swapping. He charged me about $110 for labor and new o-rings. I already had the special clamps on the quick connects. So it was near $350 plus my labor and time, more than I wanted to spend, but it fixed it. I cleaned the lines out well with the guidance of my guy, the older Fords had simple round lines, no radiator like internals, so no filter needed.