Suspension and Tire Pressure recommendations for desert/dune riding…

Just like the title says, I’m looking for recommendations for tire pressure and suspension settings for riding in the desert/dunes in my ’15 XP-4. It’s bone stock except for a windshield/roof/cargo box and most of my riding is done solo, some 2-up, occasionally 3 or 4. I’m planning on a bunch of upgrades but want to make the most of the ride in the interim…

Thanks in advance for thoughtful replies!