I took my Sierra AT4 with stock Duratracs out on the beaches last fall near Wilmington at Freeman Park and Fort Fisher. It was fall, so the sand was fairly compact and not nearly as soft as it normally is during the summer. I just aired down to 20 psi and had no issues whatsoever. Probably could've just left it alone based on the sand conditions that weekend.
During summer, the sand on NC beaches do get very soft and you do want maintain speed, keep in a good path. Airing down is absolutely required when the sand is soft. We have a '98 Tahoe we keep at the beach with nearly bald Michelin Defender LTX (if I am not mistaken) that are nearly flat, we constantly drive by new trucks that are buried out at Freeman Park at Carolina Beach who I imagine thing that 4WD means they're invincible. 9 years ago, we took our Jeep Grand Cherokee Overland with 20" sporty (and wide) rims and tires to Coralla, I doubt I aired down and did just fine both ways. Point being, airing down is always the right move, then driving at a slow/medium steady pace is the key. Stay in the ruts and give it some gas when you have to switch "lanes"