SFO domestic terminals question
I have a question regarding if and how the three domestic terminals at SFO are connected once you are past security. I fly out of Terminal 1 but I want to have a drink at the Centurion Lounge in Terminal 3 before my flight, which is air-side. Can I walk all the way from T3 to T1 once I'm air-side? Or do I need to go back to land-side to access T1?