I've tried the moving in and out thing already. I do need to test with my entire downloads folder pulled. I didn't think to pull it because it was only a problem on one lot. 

So, one of my sims will go out and try to get in their carpool, and just stand there, not opening the door, staring at the honking carpool as if they've never seen one before. They also can't get the option to drive to work when I do buy them a car, and don't appear to be using sick or vacation days.
I don't think it's the portal, as the schoolbus comes and goes just fine, as does the gardener, the nanny, the maid, etc. Also, the car eventually goes away. This may or may not be linked to the fact that I randomly had a glitch where this sim jumped to the top level of their career. I don't think it is, because my initial attempt at a fix was to have them quit and then use the computer to get back into the career from the bottom, where they had been before.

Has anyone seen this before? Does anyone know what it is? Ideally, does anyone know how to fix it? Please and thank you, I'm putting on my fire suit now.

Additional information:
I have all EP's except pets, though this showed up before I installed FT and AL.
I don't knowingly have any hacks that should affect this, and this popped up before the installation of ACR.
Assume I know nothing. You'd be right, and you're good at that anyway.