^^^No, that's the San Gabriel River.

Yeah, the bike path kind of dies in LB at Shoreline Village. You kind of have to know the area to know which sidewalks get you to the end of the LA River trail. I can't think of a good way to get to the trail in LB but an OK way would be to ride across town on Anaheim or Willow. The west side of LB is a little dicey at times (no night riding) but I ride across on Willow a few times a year.