ktj09's Tabula Recta Mystery Cache

Yes, another cache with another puzzle. The final location of this cache is hidden in a beautiful area in Pickaway County. To obtain the correct coordinates for the cache’s location, you first need to solve the following message:

The method used for encoding/decoding this message is very easy. There is a wealth of knowledge on this technique on the internet, in books, etc. However, I have made it slightly more difficult (and how I did is up to you to discover). Nevertheless, if you feel stuck later on, please feel free to ask for a clue.

While pursuing this cache, please use stealth (this is a very populated area in the summer, fall, and spring times). There are also many other geocaches in this area for you to find as well. While pursuing this cache, pay attention while hiking the trail, there is a smaller trail that can lead you back into the area where the cache is hidden without having to bushwack your way back there. The First to Find will be rewarded with a geocoin. The cache container is big enough for small trading items and bring your own pen or pencil.
Bonne chance tout le monde!

You can check your answers for this puzzle on Geochecker.com.

Check out these other caches by ktj09!