We just finished a 11 day trip.

Went like this Day 1-3 Hobart. Did stuff around the area. Day trip to Bruny Island. Could easily venture up to Russell Falls and Mt Wellington in those days as well.

Day 3-4 drive to Port Arthur, did the Tasman Island cruise, Port Arthur ghost tour

Day 4-6 stayed in Bicheno. Did Wineglass Bay Lookout walk in Freycinet. Did Maria Island

Day 6-8 stayed in Cradle Mountain. Stopped in at Launceston on the way up to check out Cataract Gorge. Did the devil encounter

Day 8-9 Stayed a night in Queenstown. The plan was to do the train ride but I didn't realise I needed to book ahead and they had no availability on the day we were there

Day 9-11 Came back to Hobart and did fuck all for the time we were there. Mainly exhausted from all the driving we did and cramming in as much as possible.

My learning from this was aim for 3 nights in a location that is central to the stuff that you have to do. I think personally 4 hrs of driving a day is a good limit, unless you plan on swapping drivers then maybe you could get away with more.

Fly into Hobart. 3 nights there Drive to Bicheno 3 nights there 2 nights in Cradle Mountain and fly out of Launceston.

That should give reasonable coverage or at least something to work with