From a distance it looks like this place might have a bit of trouble holding the 30 or so people just in this group of survivors. Jim and Anne both seem confident that there won't be a problem with that so you just have to hope they know what they're doing.
Despite both Jim and Anne reassuring the group that they were close it takes another hour to actually reach the manor and then it hits you. This place is huge. No, that doesn't cover it. This place would rival nearly any luxury resort in the world for sheer size!
Before you even reach the walls there is probably a close to half a mile of flat grassland. No trees. Bushes. Holes. Anything. This land has been cleared and then maintained to give the people in the manor a clear line of site in an entire circle of the manor itself.
The walls are made of a solid concrete, brick kind of mixture and must be three feet thick not to mention ten feet tall! Who would build something like this? Here of all places? It was clearly a fortress before everything happened... Talk about easily defensible. Even if a thousand of those things showed up the walls would be impassable until a defense could be mounted!