Rise of the Runelords
Thistletop C1 Hidden Entrance
"The briars and thistles that grow so rampantly in Nettlewood are even more dense and tangled here, close to the shore. Although not quite dense enough to block the sound of waves crashing on the unseen shores to the west, the undergrowth is certainly thick enough to block sight and access to the coast. Few trees grow this close to the edge of the sea, but the briars themselves often reach heights to rival them; here, the patch is nearly twenty feet high."
The thorns that comprise the "walls" here are quite damp; the fog every morning and evening ensures that. As a result, the brambles don't burn well. An attempt to smoke out the goblins or burn down their thistle maze only results in a slow-burning smoky fire that alerts the goblins to the PCs' precise location.
While the PCs can certainly attempt to reach Thistletop by the sea or by traveling along the beaches, they'll still need to navigate the treacherous sea cliffs to get to the stockade built atop the island. The cliffs themselves are 80 feet high, and since the damp sea air makes the walls slick, it's a DC 15 Climb check to navigate them-no easy task for most goblins, or most low-level PCs, for that matter!
As a result, the goblins created this small network of tunnels and chambers in the briars to make it easier for them to come and go. If the PCs discover these tunnels, they can certainly use them as well. A cleverly constructed rigid mat of thistles and nettles hides the entrance to the tunnels. A DC 12 Perception check is enough to notice that the briars here can be lifted aside to reveal a 4-foot-high tunnel leading into the briars. Similar "thistle doors" are within the tunnels beyond they can be discovered with a DC 12 Perception check as well. Opening a thistle door is a standard action, although a character can try to open one quickly as a move action. Doing so requires a DC 15 Reflex save to avoid being scratched and jabbed by thorns and taking 1 point of damage. A character wearing gauntlets or heavy armor automatically makes this saving throw.