The Davy Crockett variant seems to just have had a yield of 20 tonnes. Per nukemap (https://nuclearsecrecy.com/nukemap/ ) the fatal radiation range (of 500 rem) is like 500 meters. If you fire from, say, 5k the radiation exposure should be significantly lower. I don’t know how the radiation exposure scales over distance, but if it’s an inverse square law that means at 5k you’re getting like 5 rem. Which isn’t great, it’s like the equivalent of a CT scan