I can see how all of this can happen, so it’s believable. It’s exciting and adventurous. Frank Brogan’s character is heroic but also flawed; so that’s believable too. The bad guys are incredibly bad and brutal, so you will have no problem hating them and wishing for their demise. All the other characters, Rojas, Stalking Bear and the farmers were sufficiently fleshed out and interesting.
I liked the part about the perma-culture farming, food trees, pig and chicken clearing of the land. It was “food” for thought. Since Mike Sheridan is a survivalist writer, the part about farming and co-ops were needed. I will buy the next book in the series.