Caldwell, a sixth-time drink driver with four previous convictions for unlawfully taking vehicles, accelerated away. Pursued by police, he only stopped when patrol cars boxed him in.
A breath-test returned a reading of 600 micrograms.
The van was recovered, undamaged.
The incident on September 19, last year, happened after Caldwell had been drinking in the Tikipunga Tavern, in Whangārei. He told police that having had his fill, he left carrying a bottle of beer and approached the woman at the Paramount Plaza Shopping Centre carpark. She had just finished loading her groceries into her van and was about to leave.
He told police he thought the woman was his aunt from Te Awamutu - a comment that dismayed Judge Philip Rzepecky, who remarked on it while sentencing Caldwell in Whangārei District Court.
The comment was "really unbelievable", the judge said.
"You shouldn't treat your aunt like that.
"What a crazy thing to say, it sort of belies the whole night," the judge said.
Caldwell pleaded guilty to unlawfully taking a vehicle, drink-driving for a third or subsequent time – his sixth - failing to stop, and aggravated assault for reversing the vehicle towards the woman).
He was also sentenced on a separate admitted charge of disqualified driving about a month later.
Police wanted him jailed as was recommended by a pre-sentence report which assessed Caldwell as being alcohol dependent with a high risk of reoffending and harm to others if he did not stop drinking.
A prosecutor said the sixth-time drink-drive conviction alone justified an 18-20 month prison term - even before the aggravating features were taken into account.
Judge Rzepecky said it was hard to disagree but he accepted defence lawyer Braden Harris' submissions home detention was the least restrictive outcome and appropriate in the circumstances. Caldwell had self-referred for help with his alcohol problem and had prospects of rehabilitation, which home detention would enable him to continue.
There had been a positive restorative justice conference and Caldwell was lucky the complainant had been so "generous and forgiving", which particularly swayed his decision, the judge said.
At the conference, Caldwell told the woman he had since stopped drinking and offered to do household jobs for her. The judge said he hoped Caldwell would honour that offer.
Using the unlawful taking of the vehicle as the lead offence, the judge set a sentence starting point of 15 months, uplifting it by six months for the aggravated assault, and a further two months for drink driving.
Home detention conditions banned him from consuming alcohol and other drugs.
There were no post-detention conditions.
For the main group of charges, Caldwell would be subject to alcohol interlock and zero-alcohol licence provisions.
Dealing with the later disqualified driving charge separately, the judge granted Caldwell a waiver from mandatory disqualification imposing 40 hours of community work in lieu of it. He noted Caldwell had his licence reinstated a week and a half before the main set of offences.
Caldwell was warned he would be jailed for a further offence.