First of all I want to thank AMC for donating The Walking Dead to AFN which lets me watch it, albeit a week or two behind. Sure I can watch it on the internet but it isn't the same as the TV. Having a show I like on the TV is pretty cool. The last two episodes were pretty crazy, a lot of stuff came to a head.
As CZ notes the folks in this show are not survivalists. They are also not military or whatever. They would be a lot better off if anybody had half a clue how to defend anything. Failing to understand that security is the first priority of work is a problem. Also missing the good old P6 (proper preparation prevents piss poor performance) and it hurts them.
As CZ noted Rally Points are important in some situations. If you realistically may need to leave the location that you are in rally points are important. In the Army rally points are most applicable in small operations that are dangerous or complex and patrol bases (defined as a short term location where a small unit may stay for 0-24 hours). Typically for a patrol base you will have two ralley points in opposite directions. Black and Gold or Budweiser and Tyson or whatever. If you are attacked by an overwhelming force from one side you go to the other. Ideally the leader would yell the rally point that folks should head to. Rally points should be far enough away from your location to be away from whatever is happening but not so far that getting there is problematic or folks will stumble into a bunch of junk along the way. Terrain dictates as 300-400 meters in deep woods with varied terrain is probably enough but it certainly would not be in flat open terrain. Since these sort of things always seem to come up at night it needs to be a recognizable place. Folks won't get to a random arbitrary location (400 meters strait west, or whatever) at night in a chaotic situation when they can't necessarily go in a strait line. On the other hand the big clump of bamboo immediately north of the bend in the creek is a recognizable area. Granted it is easier to do this when the location you are at is fixed (vs stopping for the night or whatever).
The idea of rolling/ SOP type rally points can work in some situations. I remember seeing a show once about a con man who had a daughter. If things got crazy their rule was that she would meet him at the bus station. This worked because every town of any size has one and you can wait there with minimal scrutiny. On the other hand 300 meters back or the last terrain feature is not a great plan. Folks will get it wrong. Specifically designate a readily recognizable place.
To take a step back the point of ralley points is that if things go entirely to hell everybody can organize and consolidate at a pre coordinated locations. If you get hit hard and need to leave the leader can yell "Black" or whatever and groups will move toward that location.
The real key with ralley points is that they are readily recognizable. Invariably attacks will come at night. A plan that the ralley points are 300 meters west and east of the patrol base is fundamentally flawed. Imagine you are a soldier who just got attacked at 2 AM when you were asleep. You shove boots on your feet and grab your ruck and when your leader yells to move to the ralley point you go. Finding 300 meters to the west is seriously problematic. Folks will stop short and go long and go to the left and right. Conversely if you go for the saddle (low are between 2 hills) 100 meters short of a crossroads or an open area in a valley folks can find that.
Also if your area is not entirely secure have your bag(s) packed.
No matter how well prepared your defenses are there may come a time when your situation could become untennable with staying only resulting in death. Spreading your equipment and supplies out with some at a friends, some in caches and some at home would help decrease the pain of needing to leave.
I can't wait for next season.