dennilfloss
Past Lifer 1957-2014 In Memoriam
If the Night Watch doesn't have enough men to defend even Castle Black, why not collapse all the tunnels at CB and the remaining two castles like they've done at other (now empty) castles and fully seal the wall? That would make it much harder for the wildlings and zombie armies to pass the wall. Of course that effectively means it will also be much harder for the Night Watch to go north of the wall but it's not like they'd need to. And it will make it harder for the wildlings to flee from the zombies as they'll have to go around the 700-mile long wall to the sea but I'm pretty sure the NW sees the wildlings as expendable.