Two nights in Strahan, the Gordon River cruise, and Port Arthur properly rather than as a choice against Cape Hauy.
Montezuma Falls (3 hrs, 7 km gravel), the West Coast Wilderness Railway, or a long unhurried run down to Zeehan and back.
Queenstown gives you the 99 Bends twice plus Iron Blow and the Galley Museum. Henty Dunes and Ocean Beach give you a slower afternoon and a better sunset.
Four hours and 32 km of gravel back. The Three Falls Circuit is sealed and takes two hours.
40 min and 50 km back, and you still get the best of Gordon River Road.
The one genuinely world-class thing in Hobart. Take the ferry, not the car.
A 1.5 hr clifftop walk instead of 4 hrs, which turns Port Arthur into an unhurried afternoon and gets you home in daylight with room to spare.
Three hours under 300 m sea cliffs, seals and albatross. The best boat trip in the state.
The standard ticket is valid two consecutive days, so you could do the site properly on Day 6 and the ghost tour or Isle of the Dead on a second run down.
More beds, the penguin tour at dusk, and 30 min closer to Day 8's roads.
45 min saved by continuing north from St Marys on the A4.
Pure driving day - four passes, the Bay of Fires, St Columba Falls and nothing else.
Plateau-edge lookout with a serious drop, 10 km of gravel off the A5.
Arrive Tue 3 Nov and the Huon and Hartz day comes back, or a second Stanley night buys the Tarkine Drive.
East coast first while you are fresh.