To answer your first question, you can go to this link and enter your address and it is supposed to tell you the fire hazard for that particular spot: http://www.mofd.org/fire-prevention/do-i-live-in-a-very-high-fire-hazard-severity-zone . Obviously Orinda is a wooded community with hills, narrow roads which can make it more prone to fires, but the Moraga Orinda Fire District has an excellent reputation. There was a recent fire in a home where the occupants had taken the smoke detectors down to replace the batteries but never re-installed them, not a good idea.
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.
Many people forget to consider that while home prices in Orinda have declined a small percentage, most areas in California and the U.S. in general have declined by an even greater percentage. So, depending on where you will be moving to, you could actually make a greater profit now than you would have made back before the recession began. Sure you will be getting less for your current home now, but you will also be spending less on your next home. Without more details on where you plan to move, I can't give you exact statistics, but I think I have given you an idea of your probable situation.
Let me know if you would like me to expand upon my responce. Good luck.
Better Homes & Gardens Real Estate Mason McDuffie