Park in the Sunol Regional Park and, if you are hiking, set aside five to six hours. Be sure to take plenty of water in warm weather and cold and rain gear at other times. I am deliberately not giving more information; please do not spoil the challenge by revealing too much in your log entries.
This is a sign only cache. It has a pen and a pencil. It also has a $2 bill that is a reward for the FTF.
You may want to check out 'Terrain Challenge' Challenge No. 3