Brolga Bill's Bike Trail (BBBT)
'Twas Brolga Bill, from Rutherglen, that caught the cycling craze,
He turned away the good old wings that served him many days...

This geoart shows Brolga Bill's bike.
It is designed so you can be like Brolga Bill, and complete the trail by bike.
(and hopefully not come to the sticky end like his mate Mulga Bill)
All the puzzles are about bike riding, and can be solved with an easy online search.
The puzzle
‘Oppy’ – later Sir Hubert Opperman, a federal minister of the Menzies era – was Australia’s first cycling superstar, and he became the face of Malvern Star. He won the Australian Road Cycling Championship four times, while also making a name for himself internationally. In 1928 he won the prestigious Bol d’Or in Paris and placed highly in the Tour de France. In 1931 Oppy won the Paris-Brest-Paris road race and was voted Sportsman of the Year by a Paris newspaper.
Question: What distance is the race? (in km)

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