I went with the Toyo Open Country RT on my Duramax. They are a relatively new category of hybrid tire that sits between the AT (least aggressive) and MT (most aggressive).

I am very happy with them, both on road and off. Jury is out on longevity, as I have less than 10K miles on them.

Worth a look, for sure. Toyos have a great rep.

"What we obtain too cheap, we esteem too lightly: it is dearness only that gives every thing its value. Heaven knows how to put a proper price upon its goods; and it would be strange indeed if so celestial an article as freedom should not be highly rated." Thomas Paine