Gatland took charge of Wales after the 2007 World Cup and his wife said watching the team grow had been special.
"I was at the airport this morning picking up [Wales captain] Sam Warburton's parents ... I'd never met them before and we're fast friends now."
She and other residents of Hamilton - where Wales played Samoa and Fiji - organised for 120 visiting Welsh supporters to be billeted free in locals' homes in a bid to combat hiked accommodation rates.
The scheme has now been extended to Auckland for fans attending tomorrow's semifinal between Wales and France and could run until next week's final if Wales win.
"People that have gone home [to Wales] are emailing to say how wonderful it was and the friends they've made. It's been like the old-fashioned rugby billeting system."
Mrs Gatland and her two children, 16-year-old Bryn and 18-year-old Gabby, have stayed in Hamilton during her husband's tenure with Wales.
The pair have been married for 22 years after they met at teachers' college and it was during her time as a trainee teacher that Mrs Gatland chose the very Welsh name of Bryn.
"I taught a Welsh boy who had recently moved here [called Bryn]. I liked the name and thought, 'If I ever have a son...' I didn't know how fitting it would be."
She said the current living arrangement "had its challenges" but frequent travel meant her husband had, for example, seen most of Bryn's rugby matches for Hamilton Boys' High School.
"If you look at the big picture, a lot of people work in careers and are gone at 7am and not home until 7pm, so when we do have him we have a lot of special times."
Mrs Gatland said the World Cup had been a thrill for their extended family.
"Bryn actually turns into a Jekyll and Hyde character at the matches. He's a typical 16-year-old, hardly says anything all week and then it all comes out at the game."
Gatland is contracted to the Welsh Rugby Union until 2015, but speculation that he could become All Black coach after the World Cup has increased given Wales' strong showing.
Mrs Gatland, like her husband, has a practised answer to such talk: "Who knows. It's not the time now to even be thinking about it."