Only one or two there to pick from with huge drives between them
Going to have to set aside a school holidays during christmas and tour the southern island of down under
I think you will find the lack of camping spots on the south west of Tasmania is due to the fact there are no roads there, you need to walk in. The whole west coast is pretty unhabited bar a few mining towns. Great forests and untouched but not much if you need powered campsites with plumbed toilets. Still an equipped campsite is still no more than 2 or 3 hours drive.
Had no problems as far as paid caravan sites went, although the free internet @zeehan was hopeless, thanks be to God I had my own Optus portable modem. Optus in Zeehan was ecellent but Telstra was hopeless. Even the United servo at Zeehan would not work. Fortunately I had enough fuel to go back to Queenstown. Filled up ute and two jerry cans as well. Rained 5 days out of 7 that we stayed at Zeehan. Roseberry was also very wet, finally we got to Penguin on the NW coast and stayed there for a week or so and that was ok, except when a big gale hit. 100km + winds. Dropped the pop top and were ok. The River Breeze Caravan park at Smithton is also very good we stayed there 4 days while formalising contracts for house.