The middle section was a little slow for me. I'm not sure what tripped me up but it seemed like maybe too much was explained when we didn't really need to know. This could have easily have been it's own book, covering the next era of civilization after the virus has been loose for a hundred years. Peter and Lish were very heroic and their band of travelers (once they hit the road) reminded me a little of The Stand. The trip and all it's perils kept me reading long into the night.
And the end.... Well, I'm glad to know there will be more on the story.