Gwen is short for Guinevere yet she was never called that in the original legend. Her real, full name in Welsh was Gwyneth, Gwynifred or Gwendolyn, varied from story to story, which also explains her nickname Gwen in the TV series.
The forest river location where Morgana and Gwen attempt to escape their kidnappers appears to be the same location where Arthur and Elena ride for their picnic in The Changeling (2010)