I recently borrowed A-Z of Word Games from the library. There are lots of ideas for puzzles in there. One puzzle that I really liked the look of, 'Doublets', was invented by Lewis Carroll.
A similar cache to this one is GC3MJ6R, to help you get the idea. Word Ladder is another term for Doublets.
With doublets, you can sometimes turn an adjective into it's opposite, by changing one letter at a time. For example:
cold
cord
card
ward
warm
Note that 'cold' is at the top because it comes before 'warm' alphabetically. The same system is used in the puzzle.
(Note: Mostly it's not possible to turn a adjective into it's opposite. I tried 'abstract' to 'concrete' and got nowhere. And the fact that the two opposite words have to be same lengths rules out most pairs. So far I've found nine pairs of adjectives but I'm sure there are more out there.)
In this puzzle, I will give you some (sometimes cryptic) clues to words, and you need to work them out and put them in the right order.
Remember that the starting word is the opposite of the end word.
You need to do this with three sets of opposites.
Arranging the words in the right order is crucial (see example above).
Once you have worked out the words and their correct order, look at the formula below to construct some coordinates.
Who knows, there might be another similar puzzle nearby where you'll get to apply your Doublets solving skills 
.
Set 1
poem
toward the stern
beyond middle aged
baby newt
just arrived on the scene
rum
painting or sculpture, for example
night mammal
common relational verb (in the functional grammar sense)
sounds like a paddle?
item for catching things
consume
wager
Set 2
where race cars get new tyres
Bloke's name rhyming with 'Boss'
jetty
exist + printer's measurement
fragrant flower
average
staple in many Asian countries
Asahi is one brand of this beverage
French city or kind of biscuit
kidney or lima, for example
look/classmate
move to a more elevated position
round pastries often with meat inside
receptacles used during cooking
decays
Set 3
inform
chat/discuss
bag
hole in ground/source of water
above average height
item for pinning something in a wall
under the weather
You can find the numbers you need using the common conversion, A=1, B=2,...Z=26 and using the notation (x, y, z) for Set x, yth word, zth letter.
For example, let's say that the first word (after finding all the words and arranging them in the correct order) in Set 1 is COLD. (1,1,3) equals 12 because Set 1, word 1, letter 3 is L, and L is the 12th letter of the alphabet.
Last five digits for South:
(3,2,1) - (2,6,4)
(2,1,1) - (2,13,2)
(3,5,1) - (2,9,1)
(1,11,2) + (3,3,2)
(1,6,2)
Last five digits for East:
(3,1,1) - (2,7,4)
(1,12,2) + (1,13,3)
(2,14,4) + (1,4,2)
(3,4,4) - (2,5,3)
(2,4,4) - (1,10,1)
Checksums: S 28, E 37
At GZ take a seat on the dark stump and look down to your left. Small fingers or a wire hook will help you retrieve the cache.
Congratulations to AngelG27 for first to find!