The great outdoors is a perfect place to place traps. Whether you place the trap just outside your dungeon or somewhere on the road, wilderness traps will often take the party by surprise. Consider the following:
Goblin Rocket Snare (CR 4)
Description: When the trap is triggered, a snare tightens around the character's ankle as a small rocket fires. The rocket drags the character for 100 feet across the countryside.
Player Description: Piles of fallen leaves obscure patches of the ground.
Trap Description: A wisp of smoke curls up from the leaves as a rope ensnares your foot.
Type mechanical; Perception 22; Disable Device 18
Trigger location; Reset none
Effect: Rocket Snare Attack
(6d6 damage + target is dragged 100ft, DC 21 Reflex Save Negates)
This type of trap can serve several purposes. It can be a wake up call, smack in the face kind of trap that will keep the adventurers on their toes, especially if they aren't being cautious enough while exploring the wilderness. If anything, their characters will probably set a double watch next time!
You can also use it to set up an encounter or lead the party to the next section of an adventure. Having this trap go off just before a goblin attack can make what would otherwise be an ordinary run-of-the-mill encounter into something very exciting; a member of the party is now injured and separated from the group, with enemy combatants between her and her comrades!
After the character is dragged 100 feet, she could find a cave, a hidden temple entrance, treasure, or even a clue. Using it in this way removes the drudgery of having the characters search and miss perception checks, etc. Since it was sudden and violent, it probably won't even feel contrived, especially if you combine it with an encounter.
In the coming weeks, there will be more wilderness traps posted. In the meantime, open up the outdoors. Turn those otherwise boring treks into memorable events.