Yeah, I didn't have any students doing my exam text this year either :'(
But think of it this way - if you were a student, would you want your tutor to have an inside out knowledge of the text and be able to correct every misquote and talk about close structural features, or would you prefer they be able to advice you in terms of what you should focus on in any given prompt, and to help you fix the common mistakes you might be making?
The Contexts are all pretty closely related, in fact there are a couple of prompts that could relate to multiple areas (eg. 'Conflict occurs because people see the world differently' or 'Our identity is a product of our environment.')
In terms of understanding the background of the context and how to explore it, reading some high scoring essays should give you some idea of areas of exploration. And whatever references you've been using this year will still be relevant to other Contexts. It might be just a simple matter of taking those examples you found worked well and rehashing them in a more identity-ish or conflict-y light.
eg. the concept of the 'American Dream' which I know is dealt with in detail because of certain WR texts. This concept is about conflicting realities and how they impact our identities, as well as how we belong to the world/landscape around us. Bam - all four contexts. Obviously you'd go into greater detail depending on which one your students were focusing on, but more often than not, good examples will be applicable to multiple contexts, and in multiple ways.
For something to happen and be worth talking about, there's almost always conflict. Provided there are people involved (and especially for groups,) identity and belonging will be there. Reality is friggen everything so that one's covered. And the imaginative landscape is just a fancy-pants way of looking at internal and projected realities.
(http://24.media.tumblr.com/7dec88b9befc9578bae9b99e9ac447eb/tumblr_n5lwhpq5sA1tq4of6o1_500.gif)
Also, seven years into a study design, just googling 'conflict/id&b etc. VCE resources' should return a good handful of results to get you started :P
Once you comprehend just how generalisable and interrelated it all is, Context is incredibly easy to wrap your head around :)