If you want to visit this Bonus cache you have to answer first the 5 questions you will find at the 5 stations of Adventure Lab. At each station you will get a part of the final calculation.
FINAL
N42°51.(A*B)+C-17
E013°34.(C*D)-(B*E)+3
VG: irqv sbgb fcbvyre, zntargvpb
RA: frr fcbvyre-cvpgher, zntargvp
QR: fvrur Fcbvyreovyq, zntargvfpu