Haven't read it, but I have read Alas, Babylon. Sounds similar but definitely worth checking out.
One book I was thinking of in my post is The Postman by David Brin. In it, the post-apocalypse was triggered by a cascading series of disasters, including (non-nuclear) warfare and disease... but the final societal collapse was caused by domestic militants following a hyper-survivalist, regressive philosophy. In other words, the preppers themselves were behind the fall of America.
I've read Alas, Babylon and The Postman too, and IMHO Warday is far superior to them both. If you found those books interesting, you will eat it up with a spoon.
I don't think the prepper mentality would go that way. I think preppers would be a lot closer to isolationists with the true horror of lack of social connection to other survivors. I can see the roving marauders since that's par for the course when society breaks down. I expect emptied prisons to do the trick.
True, in The Postman the Holnists weren't just hyper-preppers, but followers of an extreme ideology that sought to reestablish a Social Darwinian, Luddite, feudal world and who actively fought the forces of order following the Doomwar. That's a different strain of thought in the real world but hey maybe some among that number might become preppers.
One book I was thinking of in my post is The Postman by David Brin. In it, the post-apocalypse was triggered by a cascading series of disasters, including (non-nuclear) warfare and disease... but the final societal collapse was caused by domestic militants following a hyper-survivalist, regressive philosophy. In other words, the preppers themselves were behind the fall of America.