This is pretty much a grab and go just past the gate at Public Shoreline Access point to the Pacheco Marsh. The container contains quite a few freebies for the kids. This is a beautiful place to get out and explore nature, see birds, rabbits, and the occassional coyote. Other than the odd coyote, be aware that conditions can be very muddy during winter months.
Pacheco Marsh is a land unit purchased by the John Muir Heritage Land trust. This is a is a wonderful organization that currently holds a number of parcels throughout Contra Costa County, and previously purchased portions or all of Mount Wanda (John Muir NM), Alhambra Ridge (EBRPD above Martinez), and Acalanes Ridge (now part of the Walnut Open Space Foundation). The property boundary extends north to about where you see to pipes in a large "V". The no trespassing signs you see between Waterfront Rd and the pipes are now moot. They are a vestige of when the area was owned by the Contra Costa Sewer district.
This cache should be a relatively easy find. A camo-ed 1 pint screw top tubberware. I specifically included quite a few kid friendly tradable items