Know that things can change rapidly there as with FCFS sites people in a site can think they are staying only to pack up and leave at noon and all of a sudden there is an opportunity. Hosts are wonderful, have them help you. when you get there...phone calling won't work.
I've had the same problem, but if you look at the reserve sign you can use the sight but be gone before the reserve date. They book up quickly.
Someone running the site, either a ranger or the host? We are just planning to go back in a few weeks so just want to verify how the sites work. I haven't been able to reach anyone by phone.
Thanks! Your answer is awaiting moderation.