how long after an event for things to die down

[Skvez]

I expect 'trouble' to ramp down rather than end which makes it hard to place a specific date on when it's 'reduced far enough'.
I voted 6 months.
People can survive for 3 months without food and most people will manage to scavange a little food from somewhere (even if they eat dogs and cats).
That will see the masses mostly die off but it will still be a very dangerous place at 6 months. Raiders will still be around and new raiders will come into existence as (the few) survivors continue to run out of food.
It may well be a generation before it's a safe to walk about unarmed and on your own as it is today (which depending on where you are isn't necessarily all that safe today).