On a misty autumn morning in Australia’s Royal National Park, just south of Sydney, a peloton of nearly two dozen cyclists tackles a 3,740-foot ascent. When they reach the highest point of the day’s 45-mile ride — the first leg of a weeklong journey — they’re rewarded with cookies and candy from support staff, followed by a downhill glide along a sandstone escarpment. Far below them, waves of the Pacific barrel toward shore and explode in clouds of foam.