There is the journey around the island, which is also a journey of the mind and imagination and in the sense that the people on it change and are then returned to their former life, the island is a stage in a journey. There is also a lot of imagination!
What age and ability are the students? I am not familiar with the HSC but I am assuming it is Secondary level or older, but perhaps not familiar with Shakespeare.
The BBC cartoon is excellent. I do strongly recommend it.
I know that before reading a Shakespeare text I do a lot of work on the plot elements so that students have a very good pictures of plot and the sequence of events and some idea of the passions and motives etc. before we even begin. I use cartoon pictures from texts (I think that the BBC do a text to go with the video) or SEN packs which have pictures which I copy and use for sequencing or matching to quotations, as well as plot summaries which they can sequence.
When I read the play we take it stage by stage. At each section (not necessarily each scene or Act) we make sure we understand what events are unfolding and how the characters feel about them before we actually read it, then we read for over-all effect. I then concentrate only on those aspects of the actual text for close study - key speeches and events - they really need to know about.
It seems an awkward play. I really enjoy it but tend to concentrate on the aspects I consider accessible/interesting to my students and use prose and plot work to fill in the gaps (i.e I skip bits!), but several of my colleagues loathe the text as a teaching text because they say many pupils dislike it and cannot relate to it at all.
Even if you can only afford a single copy, I do recommend
this edition of the play. These Cambridge Student editions of The Tempest are very good as a teaching tool as they have througout, discussion and mini-drama activities (which can often be done by the pupils whilst seated so even shy bairns do not count it as drama) for Secondary pupils to do to help them get to grips with the play and its ideas. This one is edited by the former Durham University lecturer - a superb teacher - Rex Gibbons.