The public gallery was packed for yesterday's sentencing, with family and friends of both Adams and Mrs Lea.
Rotorua Crown Solicitor Fletcher Pilditch said victim-impact statements provided to the judge showed what type of person Mrs Lea was. He said the fact she still worked - she was approaching 30 years' service with Sealed Air - showed she was a woman with a strong work ethic.
Family described her as "their rock", a "matriarch" and "close to a saint", Mr Pilditch said.
He said Adams had attended a restorative justice meeting with Mrs Lea's family which was emotionally charged but cathartic.
"It reflects well on the defendant he was prepared to partake in that very difficult process," he said.
Defence lawyer Jonathan Temm said Adams acknowledged from the outset the crash was his fault and he was genuinely remorseful. He said Adams never saw Mrs Lea and it was "a moment's inattention" that caused her death.
Judge McDonald said the five victim-impact statements showed the "kindly grandmother was well loved and respected".
"One would have to have a hard heart not to be moved by the words in those statements."
He said there was no doubt Adams caused the collision.
"You didn't see her when you should have and turned against the red arrow," he said. "You were inattentive for whatever reason."
However, there were a lot of mitigating factors, he said.
Adams had already paid $5000 reparation to Mrs Lea's family, had no previous convictions and his early guilty plea saved the family from a drawn-out process, the judge said. He had also taken part in the "stressful" restorative justice process, which helped families on both sides see each other for "the human beings that they are", he said.
Judge McDonald said home detention was not an easy sentence and Adams wouldn't be able to just "sit in his La-Z-Boy and watch TV".