The trick to driving in soft sand is how you set your tires up, you need to increase your footprint length. By reducing tire pressure and to maximize the footprint length you need to have tires with plenty of sidewall height, larger rims and small sidewall height is the reverse as to what you are trying to achieve.
Tire pressures are variable to the conditions and somewhat experimental just a another PSI lower can have a remarkable difference, you soon learn to identify sand conditions and what PSI would be best to suit those conditions. In some instances 12PSI was required to negotiate some beaches up Lancelin way.
However you must always take a compressor to make sure your tires are bitumen ready for the trip home, otherwise you might have a disaster.
