Close to the posted coordinates you will find an information kiosk. Use it to get the final.
N 49 07.ABC W 122 55.DEF
A = Briarwood Trail, first number
B = Briarwood Trail, second number
C = Lower Trail, first number times two
D = Briarwood Trail, first number
E = Gravity Bowl - Canyon Trail, distance times two
F = Lower Trail, first number times two
Checksum = 19.