Fourth in last year's Coast to Coast and having pushed Ussher hard at the 2013 Motu Challenge, Clark went back to the drawing board this year. He has rebuilt his running legs by joining the burgeoning stable of Tauranga coach and former Commonwealth Games marathoner Craig Kirkwood.
He led for 20km of March's Tarawera Ultramarathon and finished the Rotorua Marathon in 2hrs 39mins, good enough for 14th place.
"Craig got me on track for the marathon and has organised a few really painful sessions," Clark explained.
"It's been a good start to my season getting some quality training under my belt, under the guidance of a quality coach. He's an old-school runner who knows it's only going to pay dividends if it's going to hurt."
Clark is targeting a big performance at next year's Coast to Coast and the run of Braden Currie this year left a lasting impression.
"He set the bar really, really high on the run leg this year and showed what needs to be done. Competing in the marathon is part of that, trying to raise my basic running speed to be able to get close to the likes of him."
Ussher, who is a five-time Coast to Coast Champion, knows what it takes to win multisport races.
The 37-year-old from Nelson said there is something special about competing in Rotorua.
"It is a super fun course," said the two-time champion in the 50km multisport race.
"It is short and fast and is reasonably spectator-friendly, which is a great thing for the sport, as is the wide range of events to choose from - there's something for any ability to try their hand at. This event has huge potential to grow. Everyone who had never ridden in the Rotorua trails went away planning a specific bike trip back to Rotorua."
Clark is hoping that his local knowledge of the Rotorua trails will help.
He hasn't ridden a bike since November's Tour of Southland but Clark has noticed his increased running training has boosted his performance on two wheels.
He has also recently completed the King of the Harbour surf ski race and the New Zealand marathon kayaking championships at Karapiro.
The 3D race features a flat 9km kayak leg on Tikitapu (formerly the Blue Lake), followed by a 30km mountain bike leg through the Whakarewarewa Forest and an 11km forest run to finish.
"It's probably the most fun multisport course in New Zealand at the moment and the mountain bike leg would arguably be one of the best in the world," he said.
"The nasty, horrible, hilly run at the end to finish things gives it a little bit of everything and this race will be a good indicator of where I want to be for the next six months."
Although defending champion Dougal Allan (Wanaka) will miss next week's race, Ussher, Clark, Nelson's Trevor Voyce and Luke Osborne (Hastings) will ensure a quality battle at the pointy end of the field.
The annual Queen's Birthday Weekend multisport festival, now in its fourth year, continues to expand, with nearly 1000 entries last year across the wide range of family-friendly events and boasting $75,000 in prizes and giveaways.
Event director Neil Gellatly has also introduced a dedicated paddle-boarding division this year.
"Competitors have always been able to use any craft in the water stage but we're keen to recognise the surge in SUP usage around the country," Gellatly explained.
"They've now got their own dedicated division in the 25km grassroots race and we're keen to showcase our magnificent Rotorua playground to a new group of athletes."
Gellatly has also noticed a strong family focus in entries this year, with mum, dad and the kids all entering the festival.
