I would have to say earlier than 10 a.m. The campground. Quickly. Sometimes you just need to hang out and wait for somebody to leave watch for people that are packing up and getting ready to leave and talk to them and say hey are you leaving?
As early as you feel comfortable, 10AM maybe? Note that several campers stay more than one night and therefore arrive before Saturday. I hope you get your spot, but I recommend a backup plan if the site is already full. I don't know when in the year it starts to get busy so I don't know how busy it is now. Good luck and enjoy the outdoors!
Thanks! Your answer is awaiting moderation.