Biking the 300km from Mt Cook to Oamaru was the easy part.
For Mr Van Leeuwen, the nervousness was from speaking about mental health and sharing his experiences of depression and anxiety at schools along the way, as part of Mental Health Awareness Week.
It was the first time the endurance athlete had spoken in front of an audience about mental health issues.
For many years, Mr Van Leeuwen never talked about his depression and anxiety; he did not want to show weakness to his competitors.
However, after winning the Lake Hawea Epic centurion mountain bike race in April, he decided to say something publicly for the first time.
It was a big step for him to write a Facebook post about what he had been through - and he never expected he would become a face of mental health awareness by doing it.
"I remember my hand shaking to push the button and go public," he said.
The response to his post had been "overwhelming", he said.
Many people reached out to him, including other top athletes, sharing their own experiences and applauding him for sharing his.
Despite the initial nerves, speaking to pupils at Twizel, Omarama, Waitaki Valley and Duntroon schools this week had been an incredible experience, he said.
"I left Duntroon and my eyes started to well up ... the kids were so cool, so naive, but also so open," he said.
"I think out of the whole experience now of being through depression and coming out the other side of it, talking about it, I've met some of the most beautiful people of my entire life."
New Zealand suicide deaths have reached their highest level since records began 12 years ago - there were 685 suicides in the year to June 30.
For that to change, Mr Van Leeuwen said it was important to take a long-term approach - starting with the children.
"Not only that, starting with kids in the rural areas ... a lot of those rural kids and families don't get the support," he said.
"It's so easy to be isolated in the rural communities."
He hoped his "ride to wellbeing" along the Alps 2 Ocean cycle trail would be the first of many other mental health awareness events in the future.
"I really love to challenge myself and ... if that can help someone, just one person, it's worth it," he said.
