Adynaton Chase Mystery Cache

This is a three-part puzzle in which you first determine a certain adynaton, then identify a cache that it brings to mind and finally examine an object associated with that cache.

Step 1.  Determine adynaton

John Steinbeck referred to it in each of his books and Pink Floyd put it on one of their album covers.

Step 2.  Identify cache

This cache is one of mine that should leap out at you.

Step 3.  Examine cache object

Find the 2-digit numbers 68, 82, 29 and 67, and convert their location to a six-digit number. 

Add the first half of this number to the N minutes and the second half of this number to the W minutes to locate the cache.

FTF prize TBA