Ashdricky:
would it be possible to write a piece of software that plugs in to copilot and sends a signal to arduino when the "arrived at destination" message appears?
That's a good question, and the key one imo. If they have a user community or a support line it would be worth asking there. Otherwise to keep the budget down you might have to log the journey's end with a button press rather than having it sync'd to the phone. If the app can do something for you, then perhaps an IOIO board would be able to give you the interface you need.