48 hours: Newcastle or Sunderland?

I have a ticket to the Sunderland match on Saturday 11/8. I fly in and out of Newcastle, Friday through Sunday. No plans yet beyond attending the game at the Stadium of Light. Should I stay in Sunderland or Newcastle? I like walking and exploring cities, so prefer a walkable neighborhood, near transit that can get me between cities and to/from the airport. Thanks for any tips