Important advise for travellers: Due to construction works at Ground Zero, the cache has moved. The travel route and the formulas remain the same, the difference is mentioned below.
The tour plan:
PR-QF-LA-AM-DL-FI-KL-LH-SA-EK-AI-TG-CX
Where do you land?
Take the codes and transfer them to figures, using A=1, B=2, C=3 etc.
To get the coordinates, you have to calculate.
The format is: N = A°B’C’’
E = D°E’F’’
Important advise for travellers: Due to construction works at Ground Zero, the cache has moved. The travel route and the formulas remain the same, the difference to the new coordinates is mentioned below.
Put the codes for the landings in the the formulas:
A: 13-7
B: 6+7-8
C: 4*2-7 deduct 51
D: 12+7+5+1
E: 8-11 add 1
F: 10*9+3 deduct 740
Have a nice trip, and see you at Ground Zero!
To make sure you didn't get lost, you can test your solution: 
Update 13.9.2015: cache container moved to different location due to construction works. Will monitor the situation and check if it can move back after completion.