The run will be out at Briones Overlook Staging Area (NOT Briones PARK!), running the Bear Creek trail along the east side of the Reservoir. The run is out-and-back and is moderately hilly, relative to many of the trails in the East Bay. The trail is about 3.5 miles long, which makes for a 7 mile total run if you decide to go the whole distance, but as always you are certainly welcome to turn around whenever you need to.
This is a single track trail that does not allow bikes or dogs. It's in the EBMUD management lands, so you need a permit. I have one that covers up to 30 people, so we should be fine. If you do have your own permit, it would be good to bring it along just to be safe.
There is a restroom at the staging area, but there are no water fountains so be sure to bring something to drink with you. Running will commence at 6:30 PM sharp.
Take Hwy 24 east through the Caldecott Tunnel. Take the 3rd exit after the tunnel, which is for Downtown Orinda. At the end of the off ramp, turn left onto San Pablo Dam Road. After about 3 miles, turn right onto Bear Creek Road. After about a mile or so, turn left into the Briones Overlook Staging Area. This turn off is easy to miss, so drive carefully.