He has always wanted to complete the marathon and hopes to do it in about two and a half hours. The event is part of his preparation for a wheelchair rugby test series against Australia early next year.
"It's a bit of fun and a good way to start training."
Starting in Okaihau, the first 7km of the course is a gradual climb with two hills.
Leslie warns that anyone who attempts to run up and help push him uphill will get barked at.
"A few times, when I pushed up Mt Eden, some people would run up and start pushing my chair."
He explained to them that the hard push and grinding hills were part of his training.
"I don't want people doing that in Kerikeri, and anyway, that's cheating."
Leslie will take the starting line with more than 1850 racers, including fellow Wheel Blacks team-mates Maia Amai, Gavin Rolton, Nafi Lefono and Robbie Hewitt and says his number one goal is to beat them, despite the fact that they have been training.
"The last time I was in a chair was about three weeks ago for a game," he said.
"I guess, I'm the underdog."
The only protective gear that he'll wear are some adjusted gardening gloves.
He won't use a racing wheelchair because he, quite simply, doesn't own one.
"I'll be strapped in so I'll be sweet.
"The chair will take a few knocks but it's much faster than my day chair."
The Wheel Blacks chair can take hills well and has already enabled him to push a 25kms distance.
However, has never travelled the Kerikeri route and the athlete admits to having an Achilles heel.
"If I have to travel through a grass area after rain, I'll pretty much sink."
Leslie has returned home to Glenbervie, in Whangarei, for a little "work/life balance" after Rio but says he has no plans to hang up his swimming goggles just yet.
There are a record amount of wheelchair competitors in the race, with seven taking part.
Losi Harford appears to be the favourite, racing in a wheelchair more suited to the rigours of a distance race. More than 2000 people will be competing across the events at Kerikeri on Saturday.
Sport Northland chief executive Brent Eastwood said it would be a huge weekend for the mid-north, with a massive influx of people boosting the local economy.
"It is fantastic to see that once again the entries for the ASB Kerikeri Half Marathon are a fairly even mix of Northlanders and participants from outside the region," he said.
"Sport Northland's purpose is about 'enriching lives through sport' and events like this one are at the heart of achieving this."