After you complete the local adventure lab, Fort White: Pioneer Town, you will receive coordinates to the final location of this bonus cache.
You may go to the posted coordinates if you would like to stand by the side of the road and wave at cars speeding through town. OTHERWISE, I'd suggest completing the Adventure Lab, and watching closely for the final coordiantes that will then be provided. At that time, all will become clear. You are looking for a small camod container at the base of an oak tree.
OR, you COULD draw a 2-mile radius circle around THESE coordinates and GOOD LUCK FINDING IT!
Gur raq bs bar nqiragher naq gur ortvaavat bs nabgure.