This should come naturally if you go for The Hero and The Laborer achievements. Remember to explore every section of every cave and building. There are many locations you will discover without effort during the post game. If you've gone through the Everfall already in your first playthrough, remember that this achievement carries over to your second playthrough. Here is a map of the main locations in the game. This achievement is tracked in your Adventure Log and will unlock once you've reached 150 locations visited.