As was mentioned in many prison movies. The prison is like a castle except its goal is to keep people in and not out. Primarily. Though it does have the ability to keep people out generally, a few people are allowed access in a normal operating prison and has been used in the past to escape. In fact giving freedom to anyone in a prison is a possible viable escape route or hole in the defenses of said prison. So lets take a look at the prison used in Walking dead season 3 and 4. And how could the inhabitants of this prison made life a little easier for themselves in regards to sabotage and security.
The initial take over of the prison started off great. They attacked the locations they wanted piece meal. They secured a location and moved on. This is typical of the comic as well. However. Shortly after the crew secured the cell block and a few other areas they gave up and said enough. They settled for areas of the prison being over run with walkers or being unable to be secured as shown by the t.v version of the introduction of Tyreese and his group of survivors. A fatal flaw was that Ricks group allowed an obviously disturbed Rick make decisions that they knew to be wrong. This isn’t to say that every group should be trusted. Far from it. However, these people were obviously not a danger and wanted the safety that Ricks group shared. A wing could have been given to the group with provisos. Such as fix the giant hole you all came through. Debris, stones and other items could have been used to make the hole more secure. At least from mobility restricted walkers.
Once again the perimeter. Once they sounded the perimeter of the double fences, they should have created at least another perimeter. Tangle foot and pits. That would have been my minimum standard. Set beyond their water source. The out of gas cars could have been put into neutral and pushed into the woods or at least as far from the perimeter as possible. Along strategic lines of attack, road blocks and under cut the roads and have a few roving patrols. That’s why they need allies and numbers. As they gained after the governor was over thrown. Just because one threat is vanquished doesn’t mean another will never appear.
Defensive gardening. Heavy bushes could be planted or redistributed to various weak spots along the perimeter. Like places where tree are spaced pretty far part and would allow for many walkers to pass freely side by side. Poison ivy and oak should be planted liberally at a good distance away. Say quarter mile. This of course would not happen over night. However over the long term. It could be very useful. Thorn bushes could also be used. By using plants with various defenses that are often thick and tough to walk though. You limit mobility of the living and the dead. And as the engineers of the defenses, you would know the secret ways to get beyond and back into the defenses.
Guards. Military style guards and tower guards would largely be irrelevant. Spy glasses and binoculars from inside the building(s) would be more relevant to the type of living and available resources the community would have. However this would entail this. Reconnoiter of the area and finding possible threats. Creating LP/OP (Listening posts/observation posts) outside of the gates and inside the city along likely movement routes would be essential. Flare guns or fires would be a great signal for the inner guard posts to be looking for as well. Once a threat is identified. Like the governor. Then observance of the city and infiltration is essential. By our standards Tyreese and his group most likely wouldn’t be in the city. And thus would make poor allies for informants on the city. So who? Glenn of course.
In this scenario Glenn would not have been taken prisoner. But I will use two scenarios.
1) Glenn is captured with his wife as we’ve already seen. Who will we send now? How about Tyreese? Or his sister? Now like I said the infiltration will be the easy part. Let’s say that we send both Tyreese and his sister. They say they were part of a larger group and a few days ago their group was over run with walkers. They were the only ones they knew of that got away. Once inside they proceed as they did in the original show. Excel at their jobs and take notes on the community. Specifically their military capabilities. They will walk around for a week. Ask people questions about how safe they feel in the town having been there longer than themselves. Tell people you’ve seen some unfriendly settlements with military gear. And you don’t see any here. How would you defend against these types of rouges?
Ex-filtration will be more problematic. However as outstanding citizens of the community, trust shouldn’t be an issue. This may include doing terrible things to prove loyalty. It is unfortunate. However. Being sure of a threat or being sure of a non threat is important. Now you will know where to place limited resources. If they are a threat as they are a threat then knowing the enemies cards is a great bit of intel to have.
2) Glenn is not captured.
Have him sneak into the town early in the morning 1-3 am. Have him do a block by block search with say Daryl being daytime security.
Once any and all threats have been identified. Then send in an infiltrator to test the mood and intent of the community. The difference is this. Glenn will know what they have and know their capabilities. Once Glenn is in he is in for longer. A few months unless things go south. Now you will really gain some trust instead of just being a hard worker. Glenn will have to work hard at becoming a trusted ally to these people. Once Glenn is sure they are right or not right or even ally material then he must be allowed to make the decision to leave or make arrangements to make allies. However. If the people are supposed to be enemies there must be plentiful effort to provide proof.