Eastcott, assistant head of English at Rotorua Lakes High School, told the Rotorua Daily Post she was looking forward to the big weekend.
"I'm getting excited and I'm not feeling too nervous yet - that will come on Saturday," she said.
After years of minimal exercise, she took up walking to relieve work-related stress, and it was not long before she progressed to marathons.
But she had never considered doing something like Ironman until this time last year.
"I met some good friends at the athletic club, who were taking part, so I volunteered to support people I knew," she said.
She enjoyed the weekend cheering on friends in Taupo.
"Then about four days later I phoned my friend and said: can we go for a coffee and chat about this?" Soon she was training for up to 10 hours each week.
But the road to Taupo has been far from simple.
Her preparation was severely disrupted in May after developing plantar fasciitis, a painful heel problem, which left her unable to run for six months.
And she had to build up her confidence in the water after a lifetime of not enjoying swimming.
Her husband Andy, 76, was full of praise for her determination.
"All the problems she has had to solve, she has really been through the mill," he said.
"What she's done is like climbing Everest - it's a tremendous journey." Eastcott said the hardest thing about preparing for the ultra-triathlon had been sticking to the rigorous training routine.
To prepare for the swimming race, she worked with Hans Greupink, who trains the United Aquatic Sports squads at Rotorua's Aquatic Centre.
When asked about Eastcott's prospects for Ironman, Greupink was unequivocal.
"Put it this way - because of the person I saw in the water, with such an amazing mentality, I think she will pull it off. She's going to do it."
The New Zealand Ironman begins at 6.45am this Saturday at Great Lake Centre in Taupo.
