Okay then, for short term, I'd go with:

Enough potable drinking water to last me the whole stay
a decent tent/tarp arrangment for shelter
enough MREs or equivalent to last me the duration
enough toilet paper to last the duration
something to occupy my time with (a big book of Sudoku, a good knife and a pile of whittlin' sticks, or some such)

For an indefinite stay:

A self flushing triple pass reverse osmosis water purifier
a hardened shelter (metal walls, but open so it don't become a sweat box)
a darned good fishing net
a solar cooker
an SAK or Leatherman
a wind up radio/flashlight