Well I read a few threads here with somewhat similar issues and I went out to look at all of the applicable electrical connections. The positive battery cable was loose. Not very loose, but it was and had some corrosion. I cleaned the cable and the terminal and tightened them up good. Checked all of the other cables and wiring and nothing seemed to be loose. I could swear I had checked all this stuff last time I had this issue.
Hit the key and it started right up. No clicks or anything. Earlier when it died it had no power at all. Could that slightly loose cable have been the culprit all along and cause symptoms months apart? Doesn't seem likely but the car seems fine now. I'd hate to think I replaced the alt and went through the hassle of wrestling the old one out and the new one in for nothing. Either way I guess I will wait and see. The radio is dead though for some reason. It had been acting up anyways so good time to replace it.