While his wife, Marlene, packed up their equipment so they could continue their journey the next day, Mr Wilton went for an evening stroll in the surrounding quiet suburban streets.

In the same neighbourhood, Kaine Geoffrey Jones, then 22, was working on his ute and decided to take it for a test drive.

A short time later Mr Wilton was left lying on the road unconscious, having being punched once by Jones in a "fit of thoughtlessness". Mr Wilton died in hospital about two months later in February 2014.

In the NSW Supreme Court on Friday, Jones was sentenced to at least six years' jail for what Justice Ian Harrison described as an "unprovoked attack on a defenceless victim".

From the dock before he was led back to jail, Jones told his mother to "relax" when she broke down and started yelling at detectives after the sentence was delivered.

Jones, 25, had been charged with murder but on the first day of his trial last year he pleaded guilty to the lesser charge of manslaughter.

On the night of the punch, a witness standing on her balcony saw Mr Wilton cross the road and heard the sound of screeching tyres.

Mr Wilton hit the bonnet of Jones' car with his hands and said words to Jones through the driver's window, before throwing his hands up and walking away.

Jones started to drive away, before he stopped his car, got out, and called Mr Wilton to him. He then punched Mr Wilton once, causing him to fall backwards and hit his head on the road.

Jones, the court heard, drove off and tried to conceal what had happened. He parked his ute in the garage, removing a sticker from the back window and changing a black plastic covering on the roof.

When his fiancee, the registered owner of the car, told police she did not know who was driving it at the time Mr Wilton was injured, Jones told her: "You've just f---ed my whole life ... I f---ing told you what to say when it happened."

He also told his mother in another intercepted phone call: "Might as well go and f---ing own up to it with all these c---s dobbing me in." The next day he handed himself in to police.

Justice Harrison described Jones' actions as "literally inexcusable" and as "inconsistent with the civilised conduct of any normal society".

"Mr Wilton did nothing that any right thinking person could regard as provocation or incitement to anger or violence," Justice Harrison said.

"Mr Wilton's actions in apparently remonstrating with Mr Jones seem to me to be no more and no less than a reasonable response to Mr Jones' manner of driving on a quiet suburban street."

The court heard that Jones had been diagnosed with a mild intellectual disability, and he had expressed a desire to undergo anger management after being sentenced.

Justice Harrison found that he had good prospects for rehabilitation, no history of violence and had shown genuine remorse and contrition.

"The events that give rise to these proceedings are a tragedy for all concerned," Justice Harrison said.

"The Wiltons have lost an important and well-loved member of their family. Mr Jones has managed in a fit of thoughtlessness to alter the course of his life forever. Both families will have significant difficulties ever being able to come to terms with these tragic events."

Outside court, when asked if she thought the sentence was long enough, Mrs Wilton said, "It is what it is.

"It has been a long period and a long time coming.

"Nothing has changed really for me. My husband has gone but Mr Jones was responsible for that and now I've got to get on with my life."