Just a few points:
About the show itself, it featured a pandemic flu-like virus with about an 80% global mortality rate that burns itself out.
Upshots? There'd still be plenty to eat with a generalized population fall of 80% There'd be plenty of firearms and ammo too, even in California, if one knew where to trade or raid for it.
That mortality rate would also undermine the manpower and cohesion of alternate social structures like gangs. There'd be a period of near total anarchy where all social systems legitimate and illegitimate sort themselves back into some semblance of working order. MS-13 wouldn't own L.A. after a pandemic, they'd have to reconstitute first and then foray out from there. Ad hoc gangs of looters, as depicted, would be the immediate danger.
By the same token, there will be plenty of available rides sitting around and gasoline, but where can you go?
With a drop of manpower that large, all complex systems are going to crash. Power, water, medical, etc., are all going to go away for the foreseeable future. You don't want to live near a nuke plant. Yes, the fuel rods will go for about eighteen months, but chances are good that 1) you don't know how to run it; 2) It will go into automatic safe mode and into standby, and; (3) the coolant water pool the rods are immersed into will eventually boil off and a radioactive fire will begin to burn out of control when it does.
Society will reorganize among the survivors rather quickly. They depicted Henderson, Nevada as a representative example in the show of a hastily contrived "City State" having dispensed with general civil rights and imposing a rather strict martial law and rigid in/out access. Communities will reorganize where they used to always organize, at places where there is easy access to water that can be channel irrigated for agriculture and along lakes and seacoasts where fishing is possible and even rudimentary trade "shipping" even if by canoe, can be reestablished. Places like Phoenix and Las Vegas, which cannot exist without the massive power grids that make them viable, would be the absolute worst places to be.
Oh yeah the guns.
Today's choices:
Ruger 4" GP-100 in .357 Mag. Totally field strippable and I have a complete set of extra factory springs for this weapon since I put in some aftermarket Wolffs. Not magazine dependent. Fires two different calibers. Not load dependent for continued operation. Never seen one go out of time. Sights are adjustable for different loads. Still concealable.
Marlin 1894CB in .357 Mag. The cowboy assault rifle. An easy carry that shares ammo with the handgun.
Ruger 10/22. A light rifle that can be strapped to a pack. Can also provide high volume fire if it has to. Easy to maintain. Ammo can be carried in the 1k range without horrible difficulty, even if spread out among several ammo carriers. A sucking chest wound will still ruin a bad guy's apocalypse.
My choices will probably change tomorrow.