I went from Long Beach on the L.A. river trail and the sign said to do a 180 turn onto Imperial to get on the west side of the river trail. Otherwise if I kept going straight it would become the Rio Hondo trail.
So I made the turn and took the L.A. river trail till I reached and end sign at Atlantic Blvd. I crossed Atlantic and turned left onto District Blvd and took that for a while till Downey Blvd and crossed that. Then District Blvd became Leonis Blvd. The road got more narrow and I turned around and came back to Long Beach where I parked my SUV near the Seal Beach Yacht Club (Studebaker Road and PCH).
How does a rider get onto the L.A. river way up to the Griffith Park area from where I stopped?