My advice is to get there early and roam the course. The last one I went to was the Saturday round of The Barclays at Bethpage Black a few years ago and we got there early and followed Lee Westwood for a while. He was in a great mood chatted with the fans and there wasn't a big following. Followed him for a bit then sat down on the 5th green in the early afternoon when there wasn't yet a crowd and watched everyone come through, including Tiger. While everyone who was following him couldn't get close to the green, I was right on the ropes and only a few feet away from him.