Larry in the past the majority of the group came up on Sat and Sunday. And I think it has been booked on the event calendar as Sat & Sun. I have always stayed Fr thru Sun. And for some years there have been a few that did the same.
I looked at the Sleeper S.P. sites today and I booked site #56 for 10,11 & 12th, fr, sat, sun. At the time I booked it there were a few sites open across the street. I booked that site because it had more sites open around it verses other areas in the park. So If your planning on going you should look into snapping one of those sites up too. The days when you could just show up and find a empty site , I think are behind us.
I hope we have a big group this year. It has been a bit light attendance in the last couple years. Hopefully this year will be different