Plank Country

Plank Country is the first chapter of the campaign Swamp Fever in Left 4 Dead 2. The map begins with the Survivors leaving a derailed train that fell in front of a small town, which they had been using as a temporary safe room. The townspeople, who had been resisting both help and refugees, believed that they could barricade themselves in, seeing as it bordered a swamp. Unfortunately, judging by the lack of other Survivors, the plan failed, and everyone has either been killed, infected, or simply left.

Campaign
The box car has basic starting supplies; four first-aid kits and tier 1 weapons. Considering the fact that the train hinders progress further down the highway, the only way to go is through the abandoned town. The road the survivors travel down winds its way past several shacks. It is wise to check these for supplies as the director often shows its rarely seen benevolent side. In fact, it is common to reach the cable-ferry crescendo event with all four survivors brimming with pills and pipe bombs. Once the Survivors eventually reach the old cable-ferry, they should prepare to fend off the infected once the crescendo event is triggered. A common place to defend is the second floor of the nearby general store, as there are often molotovs, incendiary/explosive ammo, and pills/adrenaline. Defending next to the river is suicide as Survivors are easily knocked into the river by all manner of special infected. Not only are the Infected attracted to the sound as it moves toward the Survivors, but they keep coming while the ferry goes back. In addition the survivors can fall into the river to their deaths. The other side of the river provides no safety. As noted, tanks often spawn here, so survivors are well-advised to heal during the ferry ride across. After following a wooden plankway for a short while, a cabin appears on the left. It often holds valuable supplies, from rare weapons like the chainsaw and grenade launcher and the laser sight, to common accessories like pills/adrenaline and ammo. The Survivors are presented with a choice, to either go left or right. Both paths often hold tier 1 weapons like the SMG and pump shotgun, as well as other goodies. If you hear a witch, don't worry about which path you choose, the director has likely spawned her directly where the two paths meet. Shortly after the walkways meet, they descend into a swamp and end. However, a much humbler path of wooden planks lies to the right, and is much faster the charging directly forward into the swamp. Soon the Survivors will see a light on in the distance. It is the entrance to a sewer pipe, and as good a safe room as any.
 *  This is one of the few most likely times for a Tank appear. If you hear either before this, get ready as you will, and try to spare a Molotov or a Bile Bomb for the Tank. 

The Survivors
Now that humans are controlling the Special Infected, things can only get harder. However, they can't spawn until you leave the campsite area. That doesn't mean that you should let them have a good chance to find just the right spot, though! Hurry up and get your supplies, and get running!

This level can be very tricky for the human controlled survivors, since the infected are not bots anymore. There are some "instant kills" spots in the crescendo event area. Also, tanks may spawn after leaving the ferry.

The Infected
Chargers: You can make instant kills here. For you to finish off unlucky survivors, you must charge them into the water, making them fall to their death.

Trivia

 * This level starts off in a place with no real entrance than the way they came from, similar to Dead Air. Like Dead Air, though, it is possible they came in through a closed/unusable way (opening in the roof in Dead Air, opening and closing the train door in Plank Country)
 * At the beginning of the level, Ellis complains to Nick about why he shot the helicopter pilot. Then they argue that the pilot was a zombie and that "he wouldn't help us very much" during that time. This seems to be a running joke with the Survivors.
 * Ellis apparently thinks that the infected pilot could still have flown the helicopter judging from what he says during the argument.
 * The helicopter can be seen behind the train that is at the beginning of the chapter where you start on, If you also look at the Chopper via Noclip you can see that there is unfinished part of the map and when you look through the train you can still see the unfinished part of the map.
 * The crashed Helicopter is the crashed News Chopper 5 model that was used in Crash Course.
 * There is a jukebox Easter egg in this level.
 * Near the ferry Crescendo event, there is a Charger strung up by all limbs. It is also interesting to note that the Charger is hung in the shape of a Lambda, the logo of Valve's Half-Life series.
 * A glitch can happen near the ferry Crescendo event where a charger can push a survivor into the water and cause them to get stuck only to eventually die once the other survivors move across on the ferry
 * The PC version of Plank Country has a glitch in Versus mode that gives the survivors 500 points upon activation of the crank that calls over the river boat. The glitch also temporarily prevents the infected players from spawning.
 * The gas station at the beginning of the level has prices over seven dollars. Many times, during a crisis such as the infected outbreak, gas prices will become very expensive.
 * This is ironic, as in Left 4 Dead, you can see the survivors burning money. Apparently it still has value in some places, but not in others. This could also be the prices from before the infection hit this town, when money still might have been of value.
 * The scenario at the beginning of the level is almost exactly the same as the one for Crash Course which involves one of the Survivors shooting the pilot of the rescue vehicle, with both pilots piloting helicopters, because of pilot being infected. However, In Left 4 Dead 2, the complainer (Nick) kills the pilot while the youngest one (Ellis) complains about that the pilot is dead, while in the original Left 4 Dead, the youngest one (Zoey) kills the pilot and is being yelled at by the complainer (Francis).
 * It should be pointed out that in Versus, if an Infected player jumps into the lake in Spawn mode, it will still kill them.