You begin at the far end of the ground near the barns roof, with ladder access up onto the rooftop itself and a tarmac pathway down some steps to a switch that begins the Survival Match. Nearby is scaffolding. The largest expanse of open ground is near the collection of barker huts and kiosks adjacent to the barns, where large oak trees grow and there is more space to move.
Although the roof of the barns (accessed via a ladder) and the sunken turnstiles area (where the lever is to begin the match) are both possible places to hold out, the roof is very dangerous because Special Infected can carry you well away from your friends and drop you off the roof, causing nasty damage.
The turnstiles area is just too compact to survive there for long, although standing on the scaffold back-to-back is the best bet if you want to try. The usual location to make your stand is the barker hut courtyard. Lay down suppressing fire and projectiles by the kiosk (1) to stop incoming foes and use the open area nearby (2) for strafing and rescuing friends carried off by the enemy.
