Thanks for the clarification - as I felt that there is basically little point to the story otherwise.
The confusion from first/third person in some places is frustrating (at one point I gave up trying to understand whose mother has cancer), and there a quite a few passages in need of editing - like a record 4 whatevers in the last sentence "The Humvees soon pushed out of whatever was left of Camp Pendleton, and onto the whatever was left of the California freeway, leaving whatever was left of the old world behind, heading into whatever the world had become" (even if it is clear it/s on purpose, 3 times whould suffice).
Otherwise, in most places the writing is clear and cursive, easy to follow, and the reader can "see" quite well the scenes, and can follow what is happening. Maybe a good editing will fix also some of the other not so clear parts.
My only grip with the main character is that it does not seem to be qualified to lead, even by his own admision, and we are not given reasons to why he might possibly develop leadership abilities later on. Why would people follow him, since there is nothing special about him.
As for more details/infodump - since all the heroes have a 3 year gap in knowledge, it should be simple to find somebody competent enough to explain to them what is happening. It would not be out of place since they actually dont know what is going on.