Great points Ben.
I am tired of the woods myself.
I would imagine shooting in LA could take longer due to the number of people in the area who might want to watch the dailies.
An interesting base of operations always seems to be the nexus of the action in the original series.
Malls have been done in a bunch of Zombie movies. LA does have the Griffith Park Observatory (we are back in the trees again though.)
In the valley there is a water supply junction (Van Nuys) that would make a great spot.
LA though is mostly mini malls; malls and apartment complexes.
Perhaps an actual Movie Studio lot would be good? Like Warner Brothers Burbank Studio Lot (TBS), Disney Studios, (Universal is a bit big to use) or MGM?
Or one of the TV Lots? CBS, ABC or NBC?