Unless traffic has died down a bit, I think the only real chance of getting a first-come/first-served site is getting there relatively early in the morning and asking the camp host about potential check outs that day. In my experience this summer, nothing is actually available the day of, at least not by mid-afternoon, especially on the weekend. You may have more luck on an earlier weekday, however. This site has no cell signal whatsoever, so site availability is accurate within two days of arrival. That's why so many sites show as FC/FS - they weren't reserved in advance so there's no info on availability. Onsite, however, they have exact details and the availability will be much different
I made a reservation, so I'm not sure how it works. But I would get the as soon as you can. And the website suggests arriving Thursday, i think. Check in is at 3pm, if that helps! Reservations online are super easy tho, just go to the website here in Google maps.
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