When faced with the option to travel, the players must travel to Deep Chasm if there is no active location.
The chasm was long and dark, and filled with the noise of wind and rushing water and echoing stone.
–The Fellowship of the Ring
While Dark Tunnel is in the staging area, progress cannot be placed on Dark locations in the staging area.
The tunnel seemed to have no end. All he knew was that it was going down pretty steadily...
–The Hobbit
Response: When you travel to Forked Passage (before resolving the deep keyword), raise each player's threat by 2 to look at the top 2 cards of the Caves deck. Put 1 on top of the Caves deck and put the other on the bottom. Then, add Forked Passage to the victory display.
Progress cannot be placed on Dwarven Door while it is in the staging area.
"Dwarf–doors are not made to be seen when shut."
–Gimli, The Fellowship of the Ring
Cave Entrance gets +1 for each Dragon Sign in the victory display.
Travel: Raise each player's threat by 1.
That, of course, is the dangerous part about caves: you don't know how far they go back, sometimes, or where a passage behind may lead to, or what is waiting for you inside.
–The Hobbit
X is the number of locations in the staging area.
Travel: Assign X damage among characters in play.
The roar of the great falls drew nearer.
–The Fellowship of the Ring
Dagnir gets -10 engagement cost.
Shadow: If attacking enemy is Dagnir, the defending player must assign X damage among characters he controls, where X is 1 more than the number of quest cards in the victory display.
When faced with the option to travel, the players must travel to Narrow Stair.
Shadow: Until the end of the round, defending character cannot be readied by player card effects.
Deep. While there are 3 or more quest cards in the victory display, Desecrated Ruins gets +2 .
Shadow: Attacking enemy gets +1 
. If this attack destroys a character, each player discards a random card from his hand.