If you felt cheated by the obvious Deus Ex Machina at the end of "The Stand" by Stephen King then give this book a go. They are very much similar but "Swan Song" has a much appropriate ending than "The Stand". And the devastation is extremely graphic and bone-chilling in "Swan Song" as it is due to a nuclear world war compared to the virus pandemic in "The Stand".
Don't get me wrong here, I love "The Stand", but the climax was as abrupt and rushed as "The Postman" by David Brin. Only if King could go back in time like the protagonist in "11/22/63" and write a more fitting climax to his epic post-apocalyptic novel.