Each the five unknowns (a, b, c, d, e) contributes an equal portion of the fifteen digit solution. I recommend parking at the listed coordinates and walking to the cache.
a/b = 0.756097560975610
b/c = 4.392857142857143
c/d = 0.727272727272727
d/e = 0.485804416403785
e/a = 0.852150537634409
Pnpur vf ba gur rnfg fvqr bs gur jnyy, qbja ybj oruvaq iregvpny fgrry uvatr cyngr.