A good question.
A local answer.

If a public connection is awkward, compare a direct ride for the market visit with the cost of city parking.

Compare the landscapes, wildlife focus and full door-to-door duration of both cruises.

Keep your Richmond departure flexible and read the posted time limit; free parking is not guaranteed close to the stalls.

If not, compare an island tour or a separate rental arrangement. Confirm child seats and pickup details before paying.

If no same-day return works, consider an overnight stay or move Port Arthur to another date.

Choose Port Arthur if its history is the priority or Freycinet if you want landscapes and walking.

Plan the journey to the mainland ferry terminal and the transport you will use once on Bruny Island.

Check the live mountain forecast and road status shortly before departure; a city forecast alone cannot predict summit visibility.

Start with a compact waterfront and central walking route, then choose one main attraction that fits the ship's schedule.

Bring a warm layer and allow time for viewpoints. A cloudy summit can be very different from Hobart's waterfront weather.

A waterfront stroll, performance or relaxed drink can fill the evening without another major attraction. Dress for cooler conditions.

Keep time for car collection or hotel check-in. Do not rely on a flight arriving exactly on schedule.