
You are looking for something near the posted cords that resembles a numerical table and has traditional columns and rows. Columns should be referenced as Alphabetical and Rows as numerical so that typical table reference may be Q5 or H7 starting from the top-left corner.
The following table references will give you the coordinates for the final cache…
N E4 D10.F5 (H1-G10)
W A7 A9 (F7-D7).J9(O5-N7)
** You do not NEED to go into the Post Office to do this cache. **