The Northern Passage is being used as a checkpoint before the long route north to Zion by Jed Masterson. He and his crew will take you on their expedition if you have 75 pounds or less equipment and take no followers. However there is a level 50 Survival check which may allow you to take more, also a level 40 barter check with Ricky to ask if he will pack light to let you bring more. There is also a crate which can be used for storage.
A grave and a hollowed-out rock containing random minor loot such as ammo, can be found near the cave entrance. The rock may have "The sun is killing me" written on it.
- Sometimes the blockage preventing access will be removed when fast-traveling to the area, opening up a passage lined with lanterns leading only to a door with the option "Exit to the Mojave Wasteland", which does nothing when selected. (This is without Honest Hearts installed.)