I always was under the impression she left on her own accord because she didn't care for the show's content, at least that's what MacFarlane vaguely said on the original DVD commentaries. Then again, she easily could have been "let go" and they aren't allowed to talk about it.
This episode was very hit & miss, some gags worked really well, others fell flat. I loved the Carter video messages for his will and enjoyed the motivational poster Brian had, but the House cameos felt really tacked on and it felt like FOX was trying to "cross promote" the same way the 24 episode on The Simpsons was basically a big commercial for 24.
I also don't really find the "Roadhouse" gags very funny, what's the joke? That Peter is just saying the name of a random 80's film with Patrick Swayze? I saw the original episode and didn't find it funny then. It would be like having an episode with Peter and Quagmire becoming hitmen and after killing their victims, they turn to the camera and say "Pulp Fiction", it just comes across like the writers are trying to explain a reference.
