History of Niles - St Mary's II Mystery Cache

This is a revision for a similar puzzle which was muggled too many times.

The posted Coordinates will take you to a sign describing the History of the Saint Mary’s Church.  You will need information from this sign to solve puzzle below

Recommend this cache not be searched for on Sunday mornings 

On that sign you must find the following clues:

1. A = The day in December the cornerstone was laid.
2. B = How many miles south of Niles the Church was re-established.

Subtract B from A and add the result to the last three digits of the posted N coordinate to get the last three digits of the final N coordinate.

1. C = The last two digits of the year mission moved to town.
2. D = How many decades Father Cappon served as pastor.

Subtract D from C, then subtract the result from the posted W coordinates to get the final W coordinates.

Niles is an old Historic town.  This area was explored by LaSalle and Historic Fort St Joseph, which flew 4 different country flags, was located on the St Joseph River in what is now Niles.  The Old Sauk Indian Trail, connecting Michigan with Indiana and Illinois, came right through here. Then when Michigan Ave (Now US 12) was forged from Fort Gratiot (Now Detroit) to Fort Dearborn (Now Chicago), it came through.  When the Railroads were connecting America, the Michigan Central Railroad was surveyed through Niles. Niles was also home to two of the great names in the Automotive Industry and a Famous Author.