I live in Hyderabad at present (near Karachi). Quetta looks risky at present, though it's not clear whether foreigners are being specifically targeted (there aren't many foreigners left in Quetta these days).
You'll get a police escort through Baluchistan, if they miss you, just ask. Whether they're any real help is debatable, but at least someone is looking after you. You can stay in Police stations at night, it's also debatable whther these are any safer. Maybe you'd want to skip Quetta (great shame), and go straight to Sibi / DG Khan / Karachi then on to Lahore.
Don't let Baluchestan put you off Pakistan as a whole, you'd be crazy to miss the Northern Areas (now Gilgit Baltistan) which are totally safe.
I'll be in Quetta after a couple of weeks, so keep in touch
Daniel, in Hyderabad