I didn't even try loading the game before adding the CC to it, so it's possible that some file was corrupt beforehand and I didn't notice. (Oh, and I meant Sunset Valley, I believe. Whatever the basic neighborhood is called. Not sure why I wrote Pleasantville.) All gameplay features I can tell work just fine; the game simply seems incapable of writing a save it can actually open later on.
At this point, I'm leaning toward there being something wrong with my patches or crack. The only explicitly hack-style CC I was using was Awesomemod, but it I gather is entirely possible that some kind of, I don't know, mangled clothing file could have damaged something somehow.
Bah. Looks like I'm reinstalling if I want to play again...