John Kennedy Toole, The Neon Bible:
Okay, so Confederacy of Dunces it ain't. But it's not trying to be, either. This slim little novel, written by Toole when he was sixteen and published posthumously, brings to mind To Kill a Mockingbird or the stories of Peter Taylor, and if it isn't the equal of his other novel, well, he wrote it when he was sixteen. Unless you are, like, Salman Rushdie or Milan Kundera or something, I'm guessing you hadn't written a novel by then, so: Quiet, you.
It's a Southern Gothic bildungsroman, set during and immediately after WWII, and the rhythm of the book is slow and languorous. Breaking up monotony (the protagonist's, not ours) are revivals, bounders, fallen women singing the devil's music, and increasingly dire times at home. It does, to be fair, get a little draggy in places but then again: sixteen. By the end of the book you can see Toole's future novel peeking out from underneath the prose.
I've heard it said that Neon Bible is only for Toole completists, but I'd disagree. It doesn't have the go-for-broke insanity of Confederacy, and it unearths very little new ground as far as "Small-Southern-Town-Coming-of-Age" stories go, but it's a charming little book and manages to pull off a child protagonist without descending into mawkish sentimentality.*
Also? SIXTEEN, man. Jeez.
* Of course, when your family is so poor you cut up old clothes for curtains, and you're pretty much eating dirt for dinner to stave off the hunger pangs, it's a little hard to be that all that sentimental about it.