@Theodule The park website: https://www.nps.gov/bibe/planyourvisit/backpacking_chisos.htm
Useful info here on back country use in Big Bend. looks like lots of good stuff is available.
Big Bend was the first NP I ever visited (in fifth grade, about 1948 or so), so my personal views are a bit dated - the park has changed quite a bit since then......
one or more gifts or other benefits from the co-op.