There's a few different ways to get to this. I recommend parking on
dirt road near trail head and walk along the coast. Trail is well
defined and relatively easy walking. However be very careful of the
cliffs - grass overhangs in places. May be a little wet in places
but nothing too major.
It is a great area for bird watching (if you're into that sort
of thing).
Some more information on trail can be found at:
http://www.capebretonbirds.ca/schoonerpond.html also Michael
Haynes' book Hiking Trails of Cape Breton has some
information on it.
Cache is nothing fancy just a plain old boring ammo can with
some stuff in it. Should be an easy find. Please trade fair.