I've run this stretch about 10 times over the past 14 years. A few additions: PLEASE TAKE CARE NOT TO TRESPASS AT THE PUT-IN!!
You can put it on the EAST SIDE (river LEFT) of the bridge, either upstream or downstream of the bridge, but PLEASE do not cross/climb over ANY fences/barbed wire at the put-in, particularly just downstream (~100') of the bridge This has been a problem in the past and will continue to upset local Livermore residents who will call the sheriff if trespass issues arise. Let's respect the local landowner's private property rights and we may continue to use this put-in in harmony.
This stretch is runable EARLY season only, 1-3 week window, early-late May depending on the snowpack towards the NW of Livermore area. It is definitely not runable every year. The more water the better, but always be heads up the first mile as the water is running bank-full (hopefully) and often through trees/shrubs along the shorelines. It's a very beautiful run and class III boaters will be treated to a semi-wilderness run. The paddle across Seaman takes ~30 minutes and is also scenic.