Let's posit, for a moment, that you had millions of dollars, and notice that a major, but not world-ending apocalypse was coming.
Me ? I'd buy a farm in a remote area, with decent climate and a good water supply. Hunting and fishing areas would be a bonus, but if we actually had some sort of apocalypse, the woods would be hunted bare, and the lakes and rivers drained of catchable fish.
A sufficient variety of breeding stock for food animals (various poultry, cows, perhaps sheep, goats, and rabbits) and work animals (donkeys, horses, dogs, cats)
I'd have a few extra large-pre-fabricated buildings, one as a warehouse, another set up as a comprehensive workshop (with several generations of powered and unpowered tools for wood, metals, and perhaps stone), with sufficient power to run them. Perhaps even a smithy, if a local ore source was available, or a supply of scrap metal nearby.
And a large dead-tree library of useful books. . .
And I'd have a GROUP of people, not just a one-family survival plan. Ideally, a number of small family-scale farms, centered around the warehouses and workshops.
This should be obvious, but isn't, I suspect. . .