Activities to be shown in a full calendar
So last time I looked Civi for Drupal ships with a calendar of activities if you install the views calendar modules (and dependencies). I think its called my activities or something similar.

You should be able to tweak this to just show the activities of type for the case in question.

Just to let you know we original developed the Civi Contact Calendar Extension but we deprecated it as the functionality above was developed.

Let me know how you get on.

Best

Jamie