My F250 was over 7000 lbs empty, so I rarely took it where it could get stuck even though I was running 275/70R18's. Once I went 245/70R19.5's it limited me even more in sand but still did well on rocky trails and snow. For soft sand, I haul other vehicles with me that do much better but I was not afraid of areas where the sand is packed or wet with my 11.5K lb truck/camper combination.
My 5500 weighs over 10K lbs empty and has 225/70R19.5's. It's not a practical vehicle for soft sand, but it has already seen the packed sand on the Pacific coast.
Low tire pressure, light throttle application and traction mats are your friends in soft sand - You want to float on top of the material under your tires instead of digging into it.