Walking in the door, you wait as your eyes adjust to the
darkness. Eventually a dusty counter reveals itself, a few coins
and small trinkets on top, a few more under the glass. The old man
behind the counter eyes the object you hold in your hands and then
jerks his head toward a dilapidated wooden door in the corner. "Big
stuff is 'round back", he says, "mind you don't trip on anything in
the hall", and then returns his attention, and the tools in his
hands, to a small glinting object beneath a lighted
magnifier.
Once you've found
Grandaddy's Swap Shop, look in the front of the logbook for the
true coordinates of this cache. After that it's a bit of a
bushwhack, but through a recently forested area (so "don't trip on
anything in the hall").
I don't know the technical name for this container, but it's
some sort of large ammo can, maybe a "short 40"? See note in logs
for picture of cache container and list of initial contents.