Pismo semi regular here.
Take SALT AWAY with you in spray bottles. Spray your wheel wells and nearby areas before and after leaving the beach. Drive DIRECTLY to a local self serve car wash and wash the underside of your truck and trailer, then wash it all again followed by a rinse of the outside of the vehicles.
Sand will get inside your trailer and in your food. Sweeping, leaf blowing it if you have a toy hauler and just eating it as is are your options.
Have fun!