It is just a tunnel, but this passageway underneath Gainsborough Road between Tarantula Hill on the north and Conejo Community Park on the south provides the connection for a fun-filled day.
Tarantula Hill is the tallest peak located within Thousand Oaks, at 1,057 feet. There's a bench at the top as you enjoy the view. There's also a small, fenced-in reservoir up there. No need for trail shoes getting to the peak, as it is almost entirely paved (with the exception of the vary top of the hill, leading to the bench). You can also take a trail to near the top, directly leading to the tunnel shown above.
Conejo Community Park has a nice play area, the Conejo Valley Botanic Garden, plenty of grass and a creek that runs through the park as well as the Kids' Adventure Garden (open on Sundays only, from 11am to 3pm).
So if you’re looking for something FREE, close by and fun to do with the kids here in Thousand Oaks, this is a viable option for you.