I was out for a walk and finding some geocaches, when I found this spot and wanted to place a nice big container, but then I saw this odd thing and decided that this is the place for a micro. Sorry! 
Stage 1:
Sculpture:
A = How many X? times 4
B = How many straight cuts from one side to the other under the mouth? times 3
If you go towards the river, you'll find 4 signs. Look at the orange one.
C = How many fish?
D = 5th line, 4th word: How many letters?
Checksum: 19
Stage 2: N 49° 16.ABC W 122° 46.BDC
There is one sign:
E = Sentence in Bold under the first picture: How many words? minus 1
F = How many different types of plants are mentioned? plus 3
G = How many rabbit tracks?
H = How many photos are on the sign?
Checksum: 21
Stage 3: N 49° 16.ECF W 122° 46.BGH
There are two signs:
I = How many species? minus 4
J = How many stages? minus 2
Checksum: 5
Final: N 49° 17.CIC W 122° 46.JGC
The final is just a few meters off the trail.