Ah ha! Captain Joy posted a very similar solution on
2018-06-04.
Captain Joy doesn't modify for the number of Hunters or Prey, but the solution that determines
at what distance the Hunters are detected is identical.
I do find it really bizarre that one of the fundamental parts of a dungeoncrawl (sneaking past guards, sneaking up to guards, players getting ambushed as they camp), is left mostly unspecified. Check out, for instance, the
pathfinder 2e writeup.