We've had better luck with the Cooper ST MAXX tires on our ranch trucks than anything. My diesel spends at least 80% of it's time hooked to the hay or stock trailers. We live on a gravel road and drive more gravel than pavement with our vehicles. I have them on my 1 ton diesel, Dad's 1 ton diesel, and his 3/4 ton gas. My 3/4 ton gas and our feed truck still have Hancook mud tires on them that are a bit more aggressive. Those trucks need all the traction they can get.
I haven't found anything that blends decent mud performance with decent highway wear, especially with a trailer, better than the Coopers. They aren't perfect, just the most aggressive tire I've found that wears that well with loads.