STREGA
Explorer
Get the most gear you can get. 4.10, 4.30, even 4.56.
Get the gas truck. Nothing you listed says "diesel" to me. The need for a dually = diesel. 38" tires and 80mph = diesel. 11,000 pounds and mountains = diesel. All of our smaller Fleet trucks (under 11,000#) are gasoline. And far, far more reliable than the diesels.
If the weight you're pulling starts to get near where you'd want a diesel. But you don't haul that amount of weight enough to make a difference, I'd jump brands to the Ford. The F350 with the 6.2L and 4.30's, seems to have more power in our fleet trucks. You have to take it out of cruise and floor it to let that motor scream to get an adavantage, but the extra power is there.
The only time I recommend a dually and a gas engine, is for expo use and slide in campers. A great combo that makes no sense for work, or large travel trailers.
That nails it.