What????  Parks close for part of the season?  I never knew that!!!  Oh, ya, I live here in southern California where our parks are open year around!!!  I have never been to a park on closing day, however, considering many parks have Halloween events, I would not be surprised to see crowds (especially if the weather is warm).  If you want to know, check out the trip reports from late October of 2000. 
I love year around parks! 
________________________ 
http://home.earthlink.net/~sfmm84/  Six Flags Magic Mountain Xtreme Guide