The sites that are in the front of the park are first come first serve. The water sites are by reservation only. To check site availability, unfortunately you do have to call the office, but you can pull up a map of the entire park on the website to see what sites you may be interested in for when you call.
I believe the sites in this park are first come, first serve. If you're wanting info on which sites are still currently available you will need to call the campsite directly to inquire.
You can send them a message on their facebook page "Mcleod Park" and im sure someone will reply.
As far as I know, one just has to call their office to check.
Thanks! Your answer is awaiting moderation.