At nightfall, most people are either in the tavern, carousing, or asleep, either inside the fortress, or in their homes in the 'town' outside it. The door of the fortress are closed, and, presumably, barred from inside, and there's no sign of guards on the ground level, though the number in the ramparts has increased. The area leading up to the gate is fairly free of buildings or other cover, although it's not terribly well illuminated until you get close to the wall, where torches in sconces light up everything within about twenty feet of the wall.