The grid below is not a sudoku grid. The only thing it has in common with sudoku is that each of the digits 1 through 9 appear exactly once in each row and each column. The heavier red lines indicate that the two digits in the neighboring cells differ by exactly 1. All such cases are indicated. I've forgotten exactly which numbers go in which cells, but I do remember that cell ER is a multiple of cell GK.....oh wait, maybe GK is a multiple of ER. You know what? It might be that EK is a multiple of GR, or GR is a multiple of EK. It's one of those four, I know. 
Cache is located at 45 03.(JS)(JT)(GS) 93 15.(FS)(HT)(JR)
You can check your answers for this puzzle on Geochecker.com.
This cache was featured on the GEOCACHING PUZZLE OF THE DAY BLOG on 3/26/15.
2/25/11 I've bumped the difficulty for this up one star. That's due to the puzzle. The find would be a 1.5 at most