For either The Seagull or Mother Courage, Streep on occasion brought pizza for the people sleeping in line overnight to get tickets down at the Public. I also waited down at the Public (I live a block or so away) stopping first at Kmart to get a comfy folding beach chair in which to wait.
I think we waited about four hours.
To be honest, I don't remember which line experience was which for those two shows, but in my experience the people in those lines were generally friendly and interesting. My only complaint about lines for Shakespeare in the Park is that abrasive, annoying, loud saxophone player who hangs out at the Delacorte while people wait on in the cancelation line. He really ruins the vibe.
I was sad when they stopped giving out tix at the Public