One thing to keep in mind is that there is not very much deep sand in the desert southwest unless you are actively seeking it. You can bury your rig in sand if you are going to some of the sand dune OHV recreational areas like Imperial Sand Dunes, but a lot of the southwest is hard-packed dirt with plenty of rocks (and some mean cacti thorns). Where you tend to encounter sand is crossing desert washes, but these tend to be pretty short stretches. Having wheeled in Arizona, southern California, and southern Utah for 20 years, I prioritize sidewall toughness over tire diameter or width. I just bought my 2nd set of 255/85/16 Cooper ST Maxx because they are great all-around performers in this environment with beefy sidewalls and fairly aggressive tread pattern. 285s are a great size option too, and more widely available. If you do some research you'll find some popular off-road brands/models have notoriously weak sidewalls and don't sell well here in the desert inferno.