i go to the desert often... first thing i did after experiencing the mojave road with a stock 15 p4x was to upgrade the suspension. since it's also a daily driver i chose the OME full kit with shocks, struts, leaf packs and greasable shackles. along with bfg km3's, best mod so far! great on rocks, sand, mud and snow. road travel is amazing!
Sliders versus the aluminum steps would be a wise precaution if you are going over any kind of substantial potholes and rocks. Definitely a full size spare, and a tire repair kit. A snatch strap. A small shovel. For the ride, a big key will be to air down to 20psi or less. Maybe 15. Thus a wise investment would be a rapid deflation kit, and then a handheld high volume air compressor like a Via Air 88p or similar. It will also help to have some single stage quality shocks.