Content below copied by the kind permission of Wahroonga Farm from his post on GPS Australia Forum.
And Don't Forget
Trackable item in the cache
At the time of my visit, the cache contained one trackable.
The trackable item was Lost Keys which originated in the USA! Pretty impressive stuff.
There is more on 'trackables' here.
Oregon Geocache Wiki
This Oregon geocache wiki, may be helpful to others setting out on this grand little exercise.