Do you need to reserve

I would. Especially since summer is ending and people are trying to squeeze in one more camping trip.

You do not have to reserve a spot, but I'd advise it. I've been a few times. Normally it is pretty empty and sometimes it is full. The last time I went, we got the last site.

You don't need to book unless you want to party. It is an area with many large tables and grills

No. On the weekends just get there early.