As for the condition of the gas lines, you can track the progress of PG&E on repairing and upgrading the gas lines here: http://www.pge.com/progress/
I have an original Frank Lloyd Wright designed home for sale in Orinda and while it did have a fire in 1995, caused from a space heater, it has not been harmed by any other wild fires since it was built in 1949. So in my opinion, Orinda is just as safe a place to live as most cities when it comes to fire danger.
Oh yeah, one last comment, today happens to be a Spare the Air day so no one is allowed to burn fires at all, so today is actually more safe than most!
I hope this was helpful, let me know if you have any other Real Estate related questions.