When you are traveling while drive bike availability. If you go to Tony's Big Bikes, you will be able to get a 400cc Honda Cruiser.
Otherwise (at other shops) an older 250cc Honda or Yamaha dirt bike, or newer Kawasaki Dirt bike. Probably not ideal for two westerners, especially Burger King eating 'mericans :hide:

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Next up are the new Kawasaki 650s. They are 'Learner Legal' in Australia, with just a governer on the throttle. So not quite as daunting as you might think.
Or get two Scooters and your wife drive herself.
Cheers,
Daewoo