Searching for Pennywise is best done in the dark. Go to GZ and find the first reflector with your strong flashlight. Move to the reflector and find the next. There are two directions you may go from GZ. They both end up at the same destination. If you're not careful, you may find yourself going in circles. The reflectors work best when you hold your flashlight at eye level.
Excluding the final, all of the reflectors are rectangular. The final marker is round. Once you find the round reflector, the final cache is witin 10 ft.
This cache is part of a master series. The stamp in the cache will be needed to figure where the series finale is. You should not reveal what the stamp is to others, lest you make their journey easier.