As long as there are no archer skeletons after you, you can just stand at the entrance without leaving the dungeon; the mobs cannot jump and so are unable to get to you there. Even ghosts, at least if you stand right by the exit.

You can also use the doors to keep enemies at bay, as they cannot open doors. They can smash doors, but it takes them quite a while to do.

Definitely use a club against skeletons, and upgrade it as soon as you can. Not sure what the best weapon against ghosts is.

A tower shield is a good defence (I LOVE the new Bone Tower Shield) in melee, especially with the changes to how blocking works and timed blocking (round shields/bucklers) no longer being stupidly powerful.

As for darkness, I've not had trouble with being able to see enemies, and once I've cleared those out it's safe to take out a torch to make sure no treasure is left undiscovered.
The yellow mushrooms are pretty good in that they give off some glow that helps you see; picking the mushrooms only after clearing out enemies can be a good strategy.