Could change it up and ride the Rio Hondo/LA River path - pretty much the same route, but I found it to be a nicer path. You just end up in Long Beach instead of Seal Beach.

Or we could ride down one of them and back on the other - only downside to that is you have to get from Long Beach to Seal Beach via 2nd St & PCH for a bit. So, that might be too much traffic for some riders.