Well, Darwin to Adelaide is 3,075 km. Dunno how big your airport is, but I think this is probably further.
So far ... delays due to road-side bushfires, the odd enormous truck, and one solar car was destroyed when it's battery caught fire / exploded.
Lead cars expected in Adelaide sometime tomorrow, but it looks like being cloudy.
These solar cars are getting pretty good, if you only want to drive during the day, never carry passengers or cargo, enjoy prolonged discomfort, and aren't afraid of being squashed like a cockroach by a road-train. [/sarcasm]
Really it is about pushing the development of solar panel technology. Which is good, IMHO. There will never be practical solar cars because there just isn't enough energy falling on a car, even if collected at 100% efficiency, to run a car that meets our normal requirements.
A solar powered house, or city, however, is much more plausible.