How should I plan one day in the Huon Valley from Hobart?

Keep Mount Field for another day. It lies in a different direction from Hobart, so combining Russell Falls with a full Huon Valley route turns two good outings into too much time in the car.

If Tahune is the main goal, allow the fuller drive south and time for the walk. Check its current opening and road conditions, then build lunch or a short stop around that single destination.

Choose whether the day is mainly about towns and local food or the forest. Huonville and Franklin can make a relaxed river-town route; add one planned stop rather than trying to reach every place in an old touring list.