The 29-year-old has been getting up to nine hours of sleep a night and praying on a regular basis since carrying New Zealand's flag into the opening ceremony.
Part of the move is driven by Willis' desire to keep the same racing routines. His wife does not have Olympic accreditation access, despite Willis tweeting earlier this week that they have been "side by side every day since Beijing". The Writtle solution takes care of that.
"We're really enjoying it," says Sierra Willis. "It's peaceful, quiet and the perfect place to prepare. Nick can focus before his big event. We're really thankful Pat and Paul have opened up their home to us. They're cooking exactly what we want too. My favourite so far has been the salmon."
"They've made us feel 20 years younger," Paul Carslake says. "We didn't know what they were looking for initially. We just had a couple of spare bedrooms during the Games. I hadn't heard of Nick when I replied to the email. Then I couldn't remember his name so he was listed in my address book as 'The Runner'.
"It's fun for us because they know so many athletes in various disciplines so we're learning to watch from their perspective. We watched the opening ceremony. Nick had the biggest grin of any flagbearer."
Willis has already helped in the local community: "He came with us on the first Sunday and had a conversation with the senior minister in front of our congregation. He chatted to people and a few of them got his autograph," Paul Carslake says.
His wife Pat is equally enthused: "They're just so easy to host. It's been fascinating listening to details of what goes on in their world. They've brought us a lot of joy. We're hoping to go and watch some of the track and field in Olympic Park."
Team Willis has also been spending time in the Carslakes' garden.
"They chill out there," Paul Carslake says. "It's a chance to relax. Nick's fallen asleep in the hammock and Sierra loves the fish pond."
However, Writtle has not always been a place of calm and serenity. Just last month, the Writtle churchyard made national news when 64-year-old Peter Reeve, who fatally shot a police constable in Clacton, committed suicide with a firearm in front of an astonished 74-year-old gardener.
Reeve, who also wounded another person in the leg, had shot at his neighbours when they returned to work - and killed PC Ian Dibell, 41, when he intervened in the deadly dispute. A huge police manhunt was launched but Reeve shot himself in Writtle before the police found him.
Writtle's normal atmosphere is far more laid back. It is another venue in a transient build-up for the Willis family leading up to London. This season they've raced in places such as Heusden, Belgium and Monte Carlo, Monaco (where Willis broke the national 1500m record in a time of 3m 30.35s). They also returned to train in the Italian town of Spoleto which they loved last year.
