Barricaded Home (Jemanie) - talk to Jemanie and he will give you some insight regarding the undead and he'll also provide you with a sidequest. Try and put a pushpin on the map to this map so you'll know where you'll need to return to.
Cult Hideout - a little telling. But knock on its doors and bring the needed material and you'll be able to get in. This place leads to the Crypt below the Beggar's Nest and is one of two Routes to the Warrens of the Undead
Barricaded Home (Krestal) - talk to Krestal about the Sword Coast Boys and the leader Drawl to get insight about what's happening to Beggar's Nest.
Warehouse - this is 2nd alternative to entering the Crypts of Beggar's Nest eventually leading up to the Warrens of the Undead. You'll find Drawl here and the missing guard Walters.
Great Cemetery - This leads to the Warrens of the Damned where you face off with the Yuan Ti, Gulnan. The Great Cemetery is also where one of the tombs for the Never's Tomb is found. (Check out the Never's Tomb quest to solve this riddle)