Yup, our wiki is in need of some updating - we're going to be doing so in the next couple of weeks.
If you check the server integration libraries in the SDK, AccountManager.createRoom now has a new parameter, "deleteOnExit". Set it to true, and once your last user leaves the room and 5 minutes goes by, the room deletes itself.
As for hooks, we've been planning to update to show more of the manager nodes. You should be able to listen to collection "RoomManager", and see the "roomState" node retract an item with body "active", which indicates the room is shutting down.
In the future, we're going to make it a little easier to navigate the manager classes (not this release but some release down the line) - for now we've been waiting to determine demand for this feature. You would be the 2nd person to ask, so one more ask, and it makes it on our list =).