The coordinates are BOGUS...they just get you to the general area.
Park at 34 35.522 and 98 29.064
There are several caches in the area, two of which are required in order to find this one.
Locate Barney Rubble, and The Czheck is in the Mail. Doesn't matter what order you go to them in, but it will be necessary to know exactly how far they are from each other.
Your task is to find a spot that is exactly that same distance from each of them.
There are an infinite number of points that will fall into that criteria, but there will only be two where you will be on Tierra Firma.
Go to the location that fits, and the nearest tree is what you are looking for.