I suggest parking where I noted. Head west and cross the new bridge, then take the trail to the south. Just before you get to Rinaldi St., there is a fork to the left, down to the tunnel.
The cache is at the far end of the tunnel, then up and to the left. Look along the fence that keeps you off the 118 freeway and you will find the cache.
congrats to mcgmarauder for FTF!!!