We have spent many years camping in the Oceano, CA dunes. The salt water definitely takes a toll on equipment and requires good washes and touch up paint. Sand finds its way into every crevice every time the wind blows which is pretty much all day so just get used to finding sand all over the outside as well as the inside of the RV. We found that the plastic pallets they deliver sodas to grocery stores on works well for limiting the amount of sand we carry inside on our feet. It elevates you off the sand to wipe the feet and the sand falls through the holes.
With my TC loaded, tires @ 22 PSI front and rear and locked in 4 low I could idle just about any where I wanted too even pulling a flat bed trailer. The extra weight of the camper would actually give the stiff sidewalls the squat I needed to increase the tire footprint. I have found that I am more concerned with sand getting in the bead of the tire causing a slow leak then ever popping a bead from low air pressure.