Did you find the Girl's Pendant in the Forest? Did you ask Harold about it? That unlocks Logan in the Sawmill.
Did the bandits attack Bareshade? You can't unlock the Bandits Camp until they do. I never missed unlocking Logan, but I am betting you can't even get the attack until Logan is unlocked (he plays a key role in the Bandits Camp event).
You need to build a workshop to make a torch, or you need 5 glowshrooms in your inventory then you can ask the Day Witch OR Othra about a way to light up the dark. Choose carefully, you can only talk to one of them then the option disappears from the other one, and they have two different amulets with different properties (though both will let you explore the underground).
