Overall I liked this season more than season 1. I wasn't sure after watching season 1 if this season would work since I think season 1 ended fairly weak, except for Xavier's story, and I feel the same again.
First, I don't care about the bunker people plot. We're murdering people and no one really seems to care. I think Sinatra as a character is interesting, but if she's dead now that's fine by me.
Second, Xavier's story is excellent. It is ridiculous, but excellent. I'm guessing the reveal in season 3 will be that all his unlikely adventures were planned by our Alex supercomputer. Link meets a guy who traveled across the post apocalyptic United States, found his baby momma, has his baby, and then traveled all the way back to Colorado just to reveal the baby. There is a 0% chance of that happening.
Third, I don't recall any hints in season 1 that this show was going into sci-fi and time travel. So the season 2 reveal feels like a huge shift. I'm in, but it just feels like a huge shift.