"Dick McAninue, Grant Hurrell and Stalky Law thought I could do this job and I certainly had an empathy and an understanding of cancer," she said.
However, things weren't easy in the first years.
"It was hard work in the beginning, following in Mary's footsteps," Walker said.
"But once trust was built in the community, they did everything they could. Mary was unpaid, but I was paid as I was working across Tararua and I worked hard and in 2011, I had organised cancer support volunteers in Pongaroa as well."
Acknowledging the hard work she has put into the job, Walker said, "it's been worth it".
"I am fortunate Grant [Hurrell] has been there from the beginning. People don't realise what he has done behind the scenes," she said.
Starting on 25 hours a week, there came the recognition in the community that wasn't enough time to do the job and the Monty Fairbrother Charitable Trust stepped in to pay an 10 extra hours a week.
Walker admits it has been an all-consuming job.
"Because I live in this community, I put time into the Sunsmart campaign, health expos and fundraisers because I believe to do the job well you have to be seen in the community," she said.
"But most importantly, I've been there for the families of cancer patients. There is support for the patients but the carers don't get anything. When I go into a household we talk and talk. People appreciate what I've done and they share their stories and a lot of my work has been about building up trust with families because without trust you can't achieve anything."
Walker, known for her compassion and understanding, said she couldn't do her work without the help of Tararua communities.
"They raise money, Women's Institute members do baking for families and it's those in our communities who pull it all together to make it work," she said.
"In Pahiatua we have a great group of people who bring everything together to give great support to those who need it. In Dannevirke and Pongaroa we have hard working, dedicated Cancer Support Groups. I believe if you get your community behind you, you just fly."
In the past 12 years there have been special moments Walker will always treasure.
"In 2007 the Dannevirke Cancer Support Group had its 25th anniversary celebration. It was special, as was the 30th anniversary," she said.
"And we've had some absolutely wonderful fundraising events such as the fabulous floral theatre extravaganza by Linda Barnett and members of the Floral Art Society. And there was the donation providing four new syringe drivers for the community hospital."
Daffodil Day and Relay for Life have raised a lot of money and Walker is proud of the community's fundraising efforts.
But there has been plenty of frustration, too, as she's worked through the health system, trying to help cancer patients and their families.
"For them it can often feel like they are waiting for help for a long time and it can take time on the phone trying to deal with their issues," she said.
"Patients have to wait in line for services and sometimes things just fall around them as they face up to five or six weeks' waiting time. I can only try and ring to find out what's holding up the system. It's frustrating."
The closure of the Manawatu Gorge in April 2017 was a huge problem for cancer patients in Tararua.
"Thank goodness for the St John Health Shuttle service," Walker said.
"I leave satisfied I have done a great job and have been accepted into this community for the work I've done. The Māori community have embraced me and taken me under their wing, something I really appreciate."
Far from retiring, Walker has been asked to become a St John Health Shuttle volunteer and will also volunteer at the Fantasy Cave.
"Who knows what will crop up," she said.
