I recommend a novel which I often read as a youngster (and still read today). It's called „the cave children“, or in German original „Die Höhlenkinder“ by author A. T. Sonnleitner. Although its not post-apocalyptic, but more Robinson-Crusoe style, it really gives you an interesting and quite thorough look at an orphaned boy and a girl reinventing civilization one tool after the other - starting with only a few skills they have learned from their grandparents.
I also find interesting, that the story is set during the late 1600's in the Alps, so the two kids actually manage to get back from the stone ages to their 'contemporary' level of inventions. Finally, the author doesn't just give short hints at how they rebuild the different tools or techniques, but goes at great length to actually describe each and every step of the inventions and there are quite good illustrations.
So overall not bad for getting back to the 1600'
P.S. : It looks like there is an English translation on http://www.amazon.com/The-Cave-Children-A-Sonnleitner/dp/0875991696
, more in German can be found on Wikipedia at https://de.wikipedia.org/wiki/Die_H%C3%B6hlenkinder