The land was good, but essential to their success were the convicts, and especially the system of assignment: in return for housing and feeding the men and women assigned to them, they got seven years' free labour.
Less scrupulous masters treated their workers like slaves, but the Archers were fair employers and records show that their convicts were content - apart from John Welch, that is, who complained that "the men here teased him so much he could not bear it".
The quote is from the diary kept by William Archer's father, and it's because the family was so punctilious in preserving the past that the two properties are not only fascinating living museums but an important part of Australia's convict history with World Heritage status.
The old cow byre at Brickendon has a detailed display telling the stories of the men and women who worked there: who were, alarmingly, dosed with purgatives and laxatives, whose tobacco was withheld because of drunkenness and who were returned to the Women's Factory as "useless, being in a state of pregnancy".
Keeping the convicts under control was a real mission and central to their moral reform was the religious education dispensed; at Brickendon in a pretty little church with a shingled roof and stained-glass windows through which the sun paints stripes on a cat sleeping by the altar.
Outside, ducks waddle past, part of an impressive population of poultry ranging freely through the grounds. Hens with chicks peck under the raised wooden barn on its staddle stones, unique in the Southern Hemisphere; a chicken looking for a quiet spot to lay runs squawking out of the smithy's shop, its roof black above the furnace.
The smokehouse is equally sooty, terracotta pots piled up on the bench, hooks hanging from the ceiling. In the shearing shed, the familiar smell of wool hangs in the air, the lower walls shiny with lanolin. In a landscape that could be English, fields of wheat ripen between hawthorn hedges.
Over the road is the homestead, the green shutters against the white-painted brick giving it a Georgian feel, although it was built with an enclosed courtyard to provide shelter to workers and stock in case of attack by bushrangers or Aboriginals.
The surrounding arboretum includes oak, ash, chestnut, yew and elm trees to make the original owners feel at home, and the striped lawn is ringed by roses. It's all very pretty, but the house is still lived in by the sixth and seventh William Archers, and isn't open to the public.
Across the fields at Woolmers, however, there are 10 furnished rooms to snoop through and complete the story.
While Brickendon's focus is on the men, at Woolmers it's the domestic work done by the women who worked for the six Thomas Archers. It was as physical as blade-shearing 6000 sheep: up at dawn to shake heavy carpets, heave cast iron pots on and off the range, churn milk to make butter, stir steaming vats of jam in the heat of summer, scrub and wring and wrestle with laundry.
The rooms are furnished in full Victorian splendour: comfortable for the masters, nothing but work for the servants. Little wonder that, with five times as many men than women in the colony, they didn't stay long, preferring marriage to indentured drudgery.
Adjoining Woolmers is the National Rose Garden of Australia, with 4000 plants of 500 named varieties, from Abraham Derby to Zephirine Drouhin.
It's a relief to the spirits, after witnessing all that heavy labour and lost freedom, to breathe the perfume and enjoy the colours - though it can be hard to resist peering at the labels looking for yet more Johns, Thomases and Williams.
CHECKLIST
Getting there: Fly Air New Zealand to Melbourne, then Qantas to Launceston.
Where to stay: In Launceston, the Hotel Charles is new and stylish. Not far into the country is Quamby Estate, a golf and country club that's friendly and charming.
What to do: Visit Brickendon Historic Farm and Convict Village and Woolmers Estate.
Further information: See discovertasmania.com.
Pamela Wade went to Tasmania courtesy of Tourism Tasmania and Tourism Australia.
Find out more at Australia.com