They may be scamming people. I called to see if I could get a month, then Stacy gave me a different number to text, then immediately told me the price ($795) and asked me to zelle it without even asking what dates I want to book (most RV parks want this information when you book, it's important!!). I told her that no one has ever asked me to pay an entire month a full month before I get there. I worked her down to a deposit, then she wanted me to send a check for $250 since I wouldn't zelle. I agreed, then she gave me an address for a PO box in Vancouver, 4 and a half hours away from the RV camp! I asked her why her PO box was there, then she started ignoring me. I sent her another text two days later, and she still ignored me.
They may be overbooking and scamming people. If you have an experience like that, call the cops.
UPDATE: Their reply about first come first serve only is inaccurate. I called about a month before to reserve and she immediately asked me to zelle her a full month's payment. I had to negotiate down to a deposit; it wasn't an accommodation.