They can't keep them all out, of course. This is a job for professionals, not for every gun-loving hobbyist with a set of cammies and a little backwoods lore. Even the professionals may be in for a long siege. Rudolph has enough survival skills that he's managed to remain at large for months, and at least believes that he's capable of holding out for six months more. But that high, winter is hard.
Cover grows thin.
Tracks are not easily erased. Your very breath gives away your position. Food grows scarce. A break-in at an unoccupied cabin, or even a quick trip to town, begins to seem like an acceptable risk, and then like a necessity. And if he does slip away, those people around Andrews who have kept both their composure and their common sense will at least have untroubled consciences to sustain them as they await his capture at another place and time.