Do not attempt this cache from the freeway I5, even though your GPSr will try to take you there. Follow my directions and ignore your GPSr. Go to S Sobodan Rd off of Hwy 166. Go south and when you see an overpass crossing fwy I5, enter the frontage road on the left and follow this service road along side the freeway until you get to a crossroad to the right and you'll be very close to GZ.
This cache is within the boundaries of GC59V6E.