Borderwilds AAR and The Dungeon First Foray

When we last left our heroes, they had successfully ambushed a small rat-thing outpost.  The group split up, half to return a badly wounded hench-halfling to his home, half to clear the rat-thing warren.  So five brave heroes (sans artillery – if first level wizards can be classified as such) spent an hour and a half exploring the caves of the rat-things only to find the leader had absconded with all the loot. 
They were able to track said leader deeper into the mountains to the entrance of The Dungeon.  During the game and on a whim, I google image searched “Skull Mountain” and found this image.  This is now the official entrance to The Dungeon, which the players have christened Skull Dungeon.
Turns out this is from the Smurfs of all places.  Taking inspiration
from any and all media – a time honored OSR tradition.
Though it meant their quarry living to fight and scheme another day, the players returned to town to rest up for a week.  They returned, loaded for owlbear, and promptly triggered a shrieker.  Said shrieker alerted the goblins on level 1, who arrived en masse, and graciously offered to escort the characters to the second level of the dungeon (the Cult of Chaos) for the nominal fee of 5 gold per head.  (The goblins are playing both sides against the middle, having granted succor to the rat-things for the same price.)
Locked into the Temple of Chaos, the characters flubbed their first encounter with the leader of the cult and fought a vicious battle on the lower steps, won the day and blundered into a second ambush moments later.  They survived that ambush and had just enough time to loot the Black Library before cultish reinforcements arrived and chased them off into the safety (sic) of the goblin escort.
At the end of the day, the characters learned quite a bit about Skull Dungeon and absconded with several heavy tomes, one of which is cursed, one of which is magic, and one of which is both.  They’re going to need some help dealing with all three of those, but are looking forward making another attempt on the Temple.  As of right now, they figure 5 gold is a cheap price to pay for not fighting the goblins.  We’ll see how they feel about that when the goblins do what goblins always do.