Knockin' on Heaven's Door
Obtained from: James Stein
Difficulty level: Hard
Reward: 500 Exp, Money
This quest starts automatically during your first visit in the Lighthouse. You'll find Colin #1 next to the entrance, who will take you to James. Use the door to get to the Lighthouse's to #2. In order to complete this quest you have to help people in the Lighthouse by completing the A Ray of Hope quest.
A Ray of Hope
Obtained from: Darvin Bark
Difficulty level: Medium
Reward: 1200 Exp, Wrench
Find Marcus and fix the transformers powering the lighthouse
Darvin can be found in a lower part of the Lighthouse, next to the closed door leading to a storage room #1. You'll learn that one of men went to check two transformers, which power up the Lighthouse, but have not yet returned. Your task is of course to locate and repair transformers if needed. Definitely the fastest way to reach Marcus is to use a car. You can find one near one of transformers (1). The man can't really do any move because of zombies surrounding him #2.
Start the extermination. This shouldn't be too difficult, because initially zombies do not pay any attention at you. After all undead are dead talk to Marcus. He'll ask you to start another transformer, while he fixes this one. A second transformer is not far away (2) but watch out near bungalows and a swimming pool. Go through a damaged fence #1 and get down. Break the door and go inside. It is clear, so you do not have to worry about any attack. You need to turn on five power units #2.
Now it is time to return to Marcus (1). But be careful because right away you'll leave the power units room you'll be attacked by few double groups of infected #1. A location from which they come running from is marked on the map, so do not get surprised. Marcus will give you some money for your help and another reward can be collected from Darvin, who can be found in the Lighthouse (3) #2.