Re: post apocalyptic
A lot of the good books cover exactly those questions. Wyndham deals with the problem of knowledge - first generation scholars, second generation farmers, third generation savages - and Earth Abides deals with similar things, IIRC. I suspect there's a strange form of wish-fulfillment in the less good post-apocalypses (No more taxes! Now I can get a rifle and a shack and live like a MAN!).
Of course it depends on what has caused the apocalypse. Once a plague has passed, life might be tolerable. Less so a nuclear war. If you can get hold of it the later portions of the 70's drama Threads deal with survival after atomic war. To put it simply, life is horrible and almost everyone dies, and whatever feeble sort of human civilisation rises from the ashes will not look much like the current one.