It had been owned by a trust and was "an awful block of land", its steep eroding hillsides covered in gorse and other weeds.
It includes the Conservation Department's 4ha Waitaha Pa reserve, and the McIntoshes soon found it there was also a second pa site on Mangawhati Hill, and earthwork remaining from an 1860s redoubt.
They intend to turn the land over to forest, with native trees and deciduous trees for autumn colour along the SH4 entrance to Whanganui.
"We want it to look good. That's the pay-off for letting me burn it."
The burning had to be done.
"It was impenetrable gorse. We wouldn't have been able to get the men through," Dougal McIntosh said.
The project has the approval of the two Iwi groups associated with the pa sites, and he is enjoying learning more about their history.
Gorse and other weeds on the block were sprayed in December. He intended to make a fire plan and burn them, but a smaller rubbish fire got away on April 27, and cleared half of the property that day.
He only went home after the last fire was extinguished, at 8pm.
The rest of the sprayed vegetation will be burned in smaller fires this week, he said.
There will be a follow-up weed spray in May, and planting will begin over winter, with some trees supplied by the nursery at Whanganui Prison. There will be no pines - most of the block will be in redwoods and cypresses for eventual logging, on a 60-year rotation.
"The satisfaction will be from turning an unproductive, weedy, erodible hilly site into a forest that will be good for the environment, the river, and enhance that entrance to Whanganui."
While this fire happened without a hitch, in what is now an open fire season, rural fire officer Gavin Pryce is encouraging people to leave any burning until after the level 3 restrictions have lifted.
Luckily there have been no major rural fires during the lockdown.
"We are still trying to keep people safe. We don't want to have to get our volunteers out of their bubbles," he said.
Fire danger has now dropped to moderate, as autumn dews keep vegetation moist.