The posted coordinates are for the Fillmore Post Office. The cache is NOT in or next to the building. But, it is a good place to start to gather the necessary information. The final cache location is within 0.5 miles.
Most of the P.O. Box geocaches use a (Grid:Row:Column) system, from the original P.O. Box - Bel Air cache, to identify which P.O. boxes you need to find. My puzzle is a little bit different. You still need to find several boxes, but rather than a Grid:Row:Column number we'll give you a starting box and then some directions to get to the box you're looking for.
North = Up, South = Down, West = Left, East = Right.
e.g. "start at 100, go South 1, East 1" would mean find box 100, and count one box down, and one box to the right to find the new number.
ABC: start at 184, go South 4, West 3
DEF: start at 353, go South 2, East 1
GHI: start at 481, go South 5, West 1
J: start at 52, go East 5, North 1
The final cache location is:
North 34° AB.CDE
West 118° FG.HIJ
This P.O. Box lobby is open 24 hours a day, 7 days a week.