Da página da Greyhound na Austrália:
Remember, with our Hop On Hop Off passes, you can get on and off as many times as you like, as long as you continue to travel in one direction. Each pass is valid for 6 months from date of purchase and 3 months once travel commences, so you have loads of time to experience the beauty of Australia!
Acho que isso responde às suas perguntas?