A good question.
A local answer.

Confirm the exact stop your coach uses before choosing an airport transfer. Kingston, Civic and other stops lead to different journeys.

Compare a direct car with public transport by walking distance and luggage, not only the fare. A short city stay may justify a simpler arrival.

Start with the current rail timetable and list stations where your train actually stops and permits the tickets you need. A town on the route is not automatically an easy stopover.

A car is most useful if you plan remote nature stops or several widely separated places. If sightseeing is mainly in town, consider public transport and occasional taxis.

Treat the published bus arrival as an estimate, especially when road traffic or a rest stop could change the journey. A one-hour buffer is fragile for an important meeting.

Choose one main visit and keep the second brief, or stay overnight if both matter. Confirm any entry or tour booking before making the coach trip.

An overnight stay makes the trip much less rushed and lets you add a museum, food stop or lookout. If you cannot stay, avoid an itinerary that crosses the city several times.

Check the final transfer as well as the intercity fare. Canberra's railway station is at Kingston, while city-bound coaches may stop closer to a central hotel; map the last leg before booking.