This cache is NOT at the posted coordinates!
The Gronsfeld cipher is a variant of the Vigenere cipher. The difference is that the Gronsfeld cipher uses 10 different cipher alphabets for its key, rather than a word for the key. It was widely used in Europe in spite of this slight weakness. As always, see the attached link for a decryption tool.
opsuiuisffuxpuisffgjwfuisfftfwfogpvsx
ftupofpofgpvsuisffuisfffjhiuuxptfwfo
You can validate your puzzle solution with certitude.