How many people can land support?

[Mick]

Welcome to APOCALYPSE HALL..

99% of the worlds population have died of a plague or asteroid strike; the few survivors have lived off tinned goods and other items in the derelict cities for a couple of years, but it'll run out eventually so they've now decided to head out into the countryside to start a self-sufficient community.
At the moment the group is about 15 strong and they're thinking of setting up in this unoccupied country house, the plague got the previous owners and we buried them out back.
The hypothetical Hall is in a temperate zone anywhere in the world, so what do forum members think, does it look like a good location?