I would agree with BigBlueOx. I recently was there not overly prepared and our tent was flattened in seconds by a down pressure system. But back to the tires, I went with street tires at 30 psi ( 5 psi blow what I usually run them on the streets) I didn’t have too many problems in and around the cabin areas. There was one area where I almost go stuck in some deep sand. Reason why I didn’t want to go lower in psi is my factory tires are low profile (33 on 20 inch rim aka not much side wall) I was afraid of screwing up the rim or getting sand in between the bead. But it is doable with street tires if you drop your pressure around 20 psi like they recommend.
One thing we found is that most of the ramps were closed for bird nesting and the directions as to where we could and could not go were not clearly explained to us by the park volunteered. There are some hot shower, running water, fuel, ice, air hose, washrooms on the island which I did not know about when doing some of my research on the place.