From Sydney to Perth ( a 15 day ride) on Lambrettas, but not without rebuilding the engine, and breaking the exhaust off, twice

these are 55 mph max, 100 miles per fuel tank max, and that means the 125 miles per stretch between gas stations required planning, extra gas, and patience

https://www.hagerty.com/media/hagerty-magazine/crossing-australia-on-a-scooter-is-an-experience-like-no-other/