Some groups; like the wealthy with their multi million dollar bunkers, would be better off for a period of time. They would have it all for a time. Food, medications, clothing, tools and machinery. Will they look after themselves, will their lackies turn on them.Some areas will be Elysium like, other areas more like...Book of Eli
I just can't imagine anyone being safe for an extended period of time. At 75yrs with multiple health issues, I want no part of a world cascading into chaos.
In my mind being mobile and able to move about would be the safest way to survive.