A good question.
A local answer.

Subtract baggage, immigration if relevant, transport and the next flight's check-in deadline before leaving the terminal.

Check rental return timing and traffic estimates for the flight day before fixing accommodation.

For Phillip Island, plan the penguin evening around the child's bedtime and the drive back, not just daytime attractions.

A guided day tour removes the driving but still makes for a long day. Read its stop durations before booking.

Compare current small-group tours by actual winery list, time at each cellar door and pickup point.

Stock up on everyday supplies in larger towns before remote legs, but leave room to buy fresh food locally.

Visit one area on foot for lunch or dinner before choosing where to spend the next evening; each precinct feels different at night.

Look at recent photos of the drink and seating; a café known for coffee may have only a basic hot chocolate.

Compare the tour's route, duration and guide focus with what you want to learn; a good guide adds context, not just directions.

Use the current PTV journey planner close to travel day and compare the walking distance from the nearest stop to the market entrance.

Skip any steep or uneven walk that demands more than your mother's comfortable interval between rests.

Collect the car when leaving central Melbourne and return it after the road trip if city parking would otherwise be wasted.