How important is the bunkhouse as a setting in Of Mice and Men?

1) We first meet all the characters there, apart from Lennie and George. Crooks is barred from the bunkhouse. What is the significance of this?

2) The bunkhouse is isolated and has no immediate surroundings

3) Objects in the bunkhouse are symbolic of the social and political issues of 1930s America

4) Light and darkness are used as a stylistic device in the bunkhouse