Went a few years ago, racing started on Wed and went thru Sun. So if you show up on Wed morning till Sun you see it all.
We bought the all week pass, you can go thru the pits and go to all the partys with the racers. I thought it was the perfect amount of time. As far as getting close, we stood on the sea wall and you could see everything, they would come by at 150ft from you AWSOME!!!!!!!! Got all kinds of pics.