I worked 4 PGA events at Valhalla

Two PGA Championship, a Ryder Cup, and a Senior PGA Championship.
Huge crowds for the 3 regular tour events - large crowd for the Senior, but not near what the regular tour drew. I think this is par for the course (pun intended). And Louisville has a bigger metro area to draw from.

I was at Warren Sunday for the final round, and thought that was a decent size crowd especially considering the heat and the fact Stricker was pretty much assured of winning - no drama. Pros had nothing but good things to say about ND and the course. Had to be good PR for the University.

It wouldn't surprise me to see the Senior PGA take an event to other college courses.