This should be an easy two stager for most cachers. Park at the posted coordinates and look to the West. You will see a large blue sign. Get some information, do a little math and you will have the final coordinates.
One of the sponsors for big blue sign has a number associated with the organization. Take that number and subtract 266. Check sum for your answer is 17. Now subtract the first two digits of that number from the last three digits of the posted Westing coordinates. Next add the last two digits of the number to the last three digits of the posted Northing coordinates. Now go find the cache!