My first novel, The Kingdom of Four Rivers, was published by Equilibrium Books in 2009. This edition is now out of print. In 2010 I released The Kingdom of Four Rivers as an ebook on Smashwords. It's now exclusively available on Amazon Kindle for $2.

From http://reflexionesfinales.blogspot.com/2011/08/kingdon-of-four-rivers-review.html
Guy Salvidge's The Kingdom of Four Rivers is a post apocalyptic novel set about 300 years after a collapse, and about 400 years from the present. If you click onto the book link, you can buy an e-copy for $2, which is what I did. It is a very fair bargain for a full length novel.  I was interested in his Yellowcake Springs novel, but it does not seem to be available yet.
Guy Salvidge was born in England, but has lived in Australia since he was nine. He started his writing career young, winning a number of awards. This novel is his first published work. He has an occasional blog where he reviews and covers science fiction literary topics. For his day job, he works as an High School English at teacher at Northam Senior High School in Western Australia. Northam is just inland of Perth which sits on the Indian Ocean side of the Australian Continent. To me, the school looks like the Australian version of Hogwarts, if Harry Potter were Australian. 

The Kingdom of Four Rivers is definitely after apocalypse.  There is a tiny remnant, possibly 1 or 2% hanging on living under screening energy dooms that keep the climate temperate inside.  Outside the previously temperate portion of what is presumably China the jungle marches up to the very edges of the remaining towns. The story begins with a trading family that is a little down on its luck.  They have made a dangerous jungle passage to a neighboring town with their three wagons, only to find that demand for their agricultural products is low.When a fellow trader offers them a chance to go to the old deserted capital of Shulao in search of some deeper areas that have not yet been scavenged, they feel they must take on this risky venture. The traders are not complete rustics.  The older patriarch, and his daughter are both able to read, and somewhat understand the old writing.  They cannot repair the old technology, but they can generally figure out the simpler devices uses. 

And that is about as far as I can take you without spilling spoilers all over the place.  There are many wheels within wheels.  Although it is not hammered over your head, there is a bit of conflict between the various high aspirations of what life should be, and the practical realities and limitations of what life actually can offer. The world and characters are very well developed.  I do not recall anything that was overly graphic or sexually charged, so I don't think it would be beyond the bounds of a mature YA.   I occasionally got the names a little confused, but that settles down about half-way through the book.  There are a number of plot twists and surprises that I found to be enjoyable.  For people looking for a how to guide on post apocalyptic living, there probably is not a whole lot of practical hands-on advice:  just a little practical wisdom.