Some collected locations of chests in Jacobs Cove.
Location 1: Top of the Motel (Red Chest)
Related Mission: Welcoming Committee.
After arriving in town and activating the turrets this Red Chest can be found on top of the local motel, building has a large Motel sign in front of it. Climb up using the various implements and jump onto the roof.
Location 2 & 3: Through the North Gate (White Chest & Red Chest)
Related Mission: A Bridge Too Ned.
There are two gates that open up at different points in the main mission progression. When the north gate opens the White Chest is located directly out of the gate. The Red Chest is located on a hill which can be reached by jumping from the platform which holds the aforementioned White Chest.
These can be accessed early, without the gate opening by grenade jumping.