"It was the warmth of the local community. They were so generous."
Mr Pryor liked being without cellphone coverage or the internet, and living in nature.
While there they shot 300 hours of footage about daily life in the village and at the school in nearby Ranana. It became a 99-minute documentary, shown in New Zealand's 2012 International Film Festival and many movie theatres.
Wanganui screenings came a little later, at the Whanganui Regional Museum, at dates that suited the film-makers and museum. The makers didn't want local people to have to pay cinema prices. They spent a week in Wanganui, were at six screenings and talked to people afterwards.
The New Zealand Film Commission and CreativeNZ helped fund the film, with an additional $30,000 from Wanganui District Council. It was nominated for every documentary category and won the Best Documentary Cinematographer award at the Moa NZ Film Awards last year.
The makers took it to the Margaret Mead Film Festival in New York in October. They said Americans found the scenery gorgeous, loved the film and asked how to get to Jerusalem.
The film had its beginning when Miriam Smith, aged 11, was taken to Jerusalem because her parents wanted to see poet James K Baxter's grave. She met Sister Anna Maria Shortall, then visited the Sisters over the years while studying at university.
In 2007 she asked Sister Sue Cosgrove about filming the place.
She and Mr Pryor moved into the convent building in 2010, intent on "forging genuine relationships and finding the heart" of the place.
They took the days as they came, wandering around with camera and filming whatever happened.
"We spent as much time not filming as we were filming. There was lots of time having cups of tea."
Editing their footage down to a 99-minute documentary was difficult, but some central figures emerged. One was Sister Margaret Mary Murphy, a nun new to the river. Others were 13-year-old Chevy and the enquiring child DJ.
One shot in the film shows patched Mongrel Mob men having a party, but the two said they didn't see gang activity.
"We knew them as people. They were good dads."
Some of the children in the film did a lot of swearing, but Ms Smith said that was just a surface issue and could happen anywhere.
"Their intelligence and goodness just shines through."
In the film, Sister Sue says Jerusalem is a place of darkness and light. Ms Smith sees it as a microcosm of the world at large.
The film-makers have kept in touch with Jerusalem people, and will be back there at Christmas.
After the film Chevy went on to win the sacred solo section in a national kapa haka competition, Ms Smith said, and DJ was the delight of all his secondary school teachers.
The three nuns have been relocated in a routine reshuffle and Sister Anna Maria is now in a rest home, but there are other Sisters at Jerusalem.
How Far is Heaven will be sold at Paige's Book Gallery and the Sarjeant Gallery, and available online at howfarisheavenfilm.com.