But the judge sentenced her to four months' home detention, noting she might be able to attend university with the aid of a sponsor.
"It's difficult to comprehend a more serious example of dangerous driving," he said.
"This was offending at the highest end of the scale."
The mayhem began when McWilliams was seen drinking from a bottle of wine as she drove along Elgin Rd. When she crossed the centreline as she approached an S-bend and narrowly missed an oncoming vehicle a concerned member of the public called police.
She weaved for about 1.3km before making a U-turn and accelerating heavily, causing skid marks 26m long.
McWilliams drove at 70kmh back along Elgin Rd, failing to make a right turn at Mailer St, and crashed into a retaining wall before reversing and speeding away.
Near the driveway to the Mornington shopping area she hit a parked Ford Falcon at an estimated 65kmh, shunting it into a road sign on the footpath. She then continued to slide down the road, hitting a second car waiting to leave the shopping area carpark.
Despite serious damage to her Mercedes, McWilliams reversed and fled the scene.
She drove into Mailer St, through a give-way intersection without slowing, over a traffic island and smashed into a third vehicle, which had a 2-year-old in the rear seat.
Again she fled, driving into Maori Rd where she accelerated heavily before ploughing into a bank.
She freed herself and put her foot down yet again, leaving skid marks for 135m.
Eventually, she fled on foot and members of the public caught her about 300m away.
McWilliams was unco-operative and refused roadside breath-screening tests, the court heard.
In total, the defendant was convicted of four counts of dangerous driving, two of sustained loss of traction, two of failing to stop to ascertain injury and one of refusing to provide a blood sample to police.
The victim who had the two-year-old passenger said: "knowingly hitting another moving car and not stopping to consider the well-being of its occupants is inexcusable."
"I concur with those sentiments," Judge Turner said.
McWilliams had enrolled on a residential rehabilitation programme last month to address her alcoholism, her lawyer said, which was due to finish at the end of this month.
Her home detention would start after that, the judge ruled.
He banned McWilliams from consuming alcohol while on home detention and ordered reparation for $11,902.
She was also disqualified from driving for 18 months.