I'm going to chuck 'Wolf and Iron' by Gordon R Dickinson in. I read it as a teen and really enjoyed it - although in retrospect I agree with everything this review levels at it:
http://magazine.metaphorosis.com/review/2016/wolf-and-iron-gordon-r-dickson/For me, it was the first Post-Apoc book I read that didn't go for a mad-max-esque desert wasteland and wasn't 1970's apocalyptic fiction e.g. 'No blade of Grass', 'Day of the Triffids' or 'The Furies'. The setting is 1980's (?) USA, following a socio-economic collapse reminiscent of the fall of the roman empire. It's a fairly hopefull apocalypse and might be of interest if you fancy a slightly different direction and have read the better suggestions!

I am also trying to remember the name/author of a series of pretty cheesy PA romps I read about the same time... but it's not coming to mind yet
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Typical - hit post and it came to me!
James Barton's WasteWorld series... They are trashy, but have some good ideas in there

I also ditto Scurv on the Phillip Reeve Mortal Engines/ & Fever Crumb series. The only caveat is that they are post-post-apocalypse so to speak with society having recovered and rebuilt. Don't expect Mad Max ;-)