Doesn't leave a lot of options, does it? A narrow band of semi-arid rocky ground on the high plains, northern Minnesota (deadly cold in winter...), northern Maine (diito), arid parts of the rocky mountains, parts of Montana, etc.
I see one spot that looks promising, surprisingly enough in the eastern USA, and I happen to know land prices there are low: central West Virginia. Hard to spot for all the widely-overlapping circles!! Population density is low, no big cities, winters are BRUTALLY cold but summers are hot enough to grow even watermelons. I would guess the soil is naturally tolerably fertile too.
I thought about West Virginia after an internet pal told me to come over there. Land quite affordable. Problem is surviving without a job and sky-high local unemployment rates, probably among the highest in the country but not counted because it has been going on so long since the mines shut down. Not that I would need a local job; my current line of business does not require my presence in any particular part of the world.