Haunted Grotto

This is a terrifying location that the priests and acolytes fear to enter. Located at the back of the small plateau that houses the hidden shrine of Lathander, the entrance to the caves is through a narrow fissure that cuts into the hillside. Twenty feet high at the face of the cliff, the fissure narrows to about 5 feet high as it runs deeper into the hillside. When it opens out near chamber 1, the roof rises back to around ten feet high.
These connected chambers appear to be part of a natural cave that eroded from runoff down the cliff face. They appear to have been hewn into rough-walled chambers from their modest beginnings.
There are six areas of interest in the system, with the first containing a Banshee. The Banshee likes to venture forth at night to wail across the valley below, gliding down to seek victims on the river and road below. The shrine is galling to her, but has enough protective wards to keep her from entering it. She does like to stand in the fissure and scream through the darkest parts of the night to taunt the priests and give them restless dreams.
Most of the other chambers are inhabited by ghouls and ghasts, with 4 ghouls in room 2, 2 of each in room 3, and 2 ghouls in room 4. They love to keep to the shadows and spring out from their darkened corners to incapacitate and overwhelm explorers. The creatures in rooms 3 and 4 will converge on any party regardless of which room is entered first, attempting to flank and surround them.
Room 5 is protected from view by an illusory wall (perception DC 20 to notice). There is a flaming skull that shuffles from the tunnel to room six when anyone gets near area 5. Another waits at the entrance to area 6, which also holds a poltergeist (specter). The poltergeist has no understanding of why it haunts this place, but was probably the being responsible for creating the flaming skulls and setting them to guard area 5. It will be drawn to any signs of a skirmish in the caves, joining any ongoing fight after 5 rounds to violently shove individuals and make it presence felt.
The flaming skulls have been set to guard area 5, which is a concealed chamber hidden behind an illusionary wall. Inside the small room are two battered and decaying wooden chests. If someone tries to lift one, it will crumble, setting off a poisoned needle trap in the lock mechanism. There is really no way to disable the trap, since any handling of the chests will cause them to disintegrate, setting off the mechanism. Any poison on the needles has dried out and become harmless, but setting them off will require a dexterity save (DC15) to avoid the needles, which cause 2d4 damage.
Inside the chests are 150 gp, 200 sp, a wand, three potions of healing (weakened from time to give 3 hp when drunk), four parchment scrolls rolled up in small metal spell tubes, and a map drawn in badly faded ink on a rolled up piece of leather. The map is in an archaic language that resembles dwarven, but is too faded to read without several hours of study (code for "I just thought of this and don't know what it is a map of").