Domestic water filters, which at a cost of $65 each have transformed livings standards in the remote community of Garam Besi, have been delivered to 130 homes, a school teacher's salary paid, and a health clinic planned.
Neighbouring villages sent delegations asking for water filters, meaning more fundraising and trips are needed.
Each journey comes with unexpected reminders of his son. Conversations with German and American travellers at the Nirvana Hotel in Pokhara revealed both knew Tony. When lost in the back alleys of Kathmandu he stopped a British woman to ask for help only to find she'd heard of the tragedy and Tony's death.
"She had friends working in Pokhara who had told her about it. Those sorts of things are quite overwhelming, to think it echoed to the UK."
On Monday a special assembly will be held at Elim, in Howick, to mark five years since the death of six of its students and Mr McClean, a 29-year-old teacher at the school.
Many of the families of those who died have refused to let the tragedy overwhelm them, instead holding to the silver linings to come from it.
But there are still pauses and carefully-chosen words when speaking of the events of that day, their causes and the people involved.
On the afternoon of April 18, 2008 a group from Elim found themselves trapped in a rocky crevasse by rising water while on an excursion into the Mangatepopo Gorge.
A plan was made for the students to enter the swollen stream and swim a short distance to the safety of a riverbank, where Sir Edmund Hillary Outdoor Pursuits Centre (OPC) instructor Jodie Sullivan had moved in an effort to pull them in as they went past.
Survivors later recounted how Mr McClean reminded the scared students of the hot showers that awaited them back at base, and took the time to pray with each pupil before they entered the torrent.
He and six students ultimately perished after being swept down the flooded gorge and flung off a dam on to rocks and massive logs.
Mr McClean, a surfer and strong swimmer, was the last to leave the ledge, and bound himself to disabled student Tom Hsu, 16, before entering the water.
Another student, Anthony Mulder, 16, was bound to friend Floyd Fernandes, who was frightened of going alone.
Anthony and Mr McClean were discovered a considerable distance below the Mangatepopo Dam, still attached to their friends. Both were honoured with posthumous NZ Bravery Star awards in a ceremony at Government House in 2011.
Speaking to the Weekend Herald this week, John McClean said his family had pulled through by holding on to the good that had come from his son's death.
"There is a gap there, but I see the adventures that we've had in Nepal, and continue to have, as a gift from Tony. I just wish I could enjoy it with him.
"We are doing well. Our family has grown and moved on. We have filled that gap with various good things. Particularly, one good thing is our first grandchild [Jessica, born six weeks ago]."
That sentiment is echoed by Andy and Nikki Bray, parents of Natasha, who also lost her life in the flash-flood. A documentary made about her death, Jumping in Puddles, has inspired charitable efforts to help disadvantaged children in the Ukraine.
"Those sorts of things really encourage you. You need to hang on to those things. There's got to be something for the price of it all," Mr Bray said.
They and their children Olivia, now studying at Auckland University of Technology, and Benjamin, in his last year of school, will attend the special assembly.
Not all the families will attend. Floyd Fernandes' family have moved to Australia, and others prefer to mark the date in private.
Elim principal Murray Burton said his conversations with the families revealed each was at a different place five years on.
"Some are happy to talk about it, and others, I think the enormity of it still rises up, particularly at this sort of time."
The faith-based school has doubled in size since the tragedy, and split into a junior and senior school. There are now only two siblings of those who died left at the school.
"The question has to be asked now as to how do you meaningfully remember it, without getting so entrenched back in the absolute grief and sadness of it all?"
But, in the end, Mangatepopo was part of the school's DNA, Mr Burton said. Under his leadership the school has not fought nor denied that.
In those terrible first days tea and coffee was brought out to the reporters who descended on the school. Siblings of those who died wrote a book, Never Be the Same, to help support one another, and two years ago a special climbing wall was dedicated to those lost.
Mr Burton, who received the insignia of a Member of the NZ Order of Merit for his central role in Mangatepopo's aftermath, said the tragedy was behind the school's growth.
Their roll cap had been approved to double to 1000 students, and permission granted to lease and build on Crown land.
"It's tough to say. The tragedy brought us a certain significance, which helped the wheels turn."
Nikki Bray, who has been on the school's board for three years, said the sensitivity and compassion shown by Mr Burton had been a part of her family's recovery.
"He seems to have always said the right thing, it hasn't been too much, but it hasn't been too little, either. He seems to have got that balance right.
Mr Burton had always told the parents that he would make mistakes, and they should call him on them, Mrs Bray said.
"There have been a couple of occasions where I've emailed him and said, 'can I just draw your attention to something?'.
"It's not until you've lost a child that you understand."
But there is still pain and some anger at what happened five years ago.
In 2009 the Turangi-based Outdoor Pursuits Centre was fined $480,000 over the canyoning accident.
At the time the judge said that given the weather forecast the group should never have been in the gorge that day.
OPC based decisions on an outdated weather forecast, missing the word "thunderstorms".
A coroner's report found the fateful decision to enter the gorge was wrongly left to instructor Jodie Sullivan, whose inexperience led her to believe there was no significant danger, despite heavy rain.
A police investigation into the tragedy found no evidence of criminal offending.
Catherine Linnen, whose daughter Tara Gregory died in the gorge, said she felt that individuals, such as Ms Sullivan, who did not respond to a request for comment, should have been held to account.
"I'm not saying I want anybody to go to jail ... but I really feel that there were individuals involved who should have been accountable."
The secondary school teacher, who calls herself the "feisty one" of the parents, said her daughter's life was wasted.
"[Now] you are not in shock all the time. You certainly miss them on significant occasions, like my father just turned 90, and she wasn't there to celebrate. Her best friend got married and she wasn't there to be a bridesmaid.
"And you look at how much her life was wasted. All these chances that she will never have. I don't think that feeling ever goes away."
Ms Linnen said incidents like the deaths of two Spotswood College students and their instructor while rock-climbing last year showed the Government had not done enough to regulate the outdoors adventure industry. She wants a practising licence for instructors, for example.
This month new adventure tourism safety guidelines were introduced for canyoning, caving and indoor rock-climbing operators following a Government review of safety in the sector.
Safety audits, which will require operators to adopt the Tourism Industry Association guidelines, will become compulsory by November next year.
Tourism Industry Association (TIA) advocacy manager Geoff Ensor said the guidelines were effectively a licensing system for operators, and arose from tragedies like Mangatepopo. He said TIA felt it was unnecessary to have every individual in the sector licensed, "but we do believe competency must be measurable and shown to be achieved".
Graham Seatter, chief executive of the OPC, said the centre had overhauled its systems since the tragedy, acting on all the coroner's recommendations including weather monitoring and approvals for activities.
He and a majority of the staff had joined OPC in the years following the tragedy, but it was never far from their minds. Last year's anniversary saw two memorials to the victims unveiled in a ceremony attended by many of the families and Elim staff.
"That was a clear statement from our organisation that we will not forget those kids and that event."
It was "highly likely" that the gorge would soon be properly re-opened to regular use by school and other groups - a move supported by many of those who attended last year's memorial.
"[Mountaineer] Graeme Dingle established OPC at the location he did because of the gorge. It defined us in our beginning, and it continues to define us."
John McClean, who said he feels regret, but not anger over the tragedy, said he was in favour of the gorge re-opening.
Since the tragedy he and his family had retraced their son's route up the gorge with OPC instructors.
"It's the most beautiful place," he said.
"But it's like it is now - it hadn't rained since December, and it was April 15. It was bucketing down, and that gorge drains half the side of Tongariro.
"It was only a matter of time before something - a steam-train of water - came down that. And people were looking in the other direction."
Killed in the deluge
Teacher Tony McClean and six students from Elim Christian College in Auckland.
Natasha Bray, 16
Portia McPhail, 16
Huan (Tom) Hsu, 16
Anthony Mulder, 16
Floyd Fernandes, 16
Tara Gregory, 16
