Easy, mystery cache for all to do. Go to the posted coords, look at the sign. The sign has a gate number. Add .507 to the North coords plus the number on the sign, using the number on the sign at the end, to get the final North coords.
N42 35.XXX
NOW: Subtract .271 from the West coords minus the number on the sign using once again that number at the end, to get the final West coords.
W72 30.XXX
At the posted coords, the road is a public road. All you need to do is pull over and look at a sign, thats it.
When I say at the end, in trying to figure this out, that means all the way to the right
First bit of help, when you subtract on lets say on a piece of paper, do not use the decimal point. Use the last 3 numbers to add or subtract.