Need help Comparing TV's for gas mileage

[Loraura]

I'd say look for a used 2013 or newer Diesel. The exhaust brake and tow mirrors are worth every penny. The heavier engine will afford you much better control in weather that isn't ideal. We get around 15-16 MPG in town and just took a 500 mile trip (no trailer) getting 20mpg. This is with aggressive off-road tires. I'd expect 1-2 MPG better without the knobby tires. We traded in our 1500 RAM 5.7L gas truck for it, and I have absolutely no regrets.

[CMelder]

For comparison, 2006 Ford F250 CC LWB 4x4 with 5.4L Gas engine & 3.73 gears, currently 275,000 miles on it (very durable). Like you, pulled a 14,000 lb. 5er 10% of the time. She gets 14.5mpg on highway empty, and 7.5-8.0mpg pulling the 5er at 70mph in southern flat states.
As you will note in my signature, I have purchased an F350 with 6.7L PSD because I was headed to Colorado and the 5.4L gas w/3.73 gears wasn't going to cut it.
The newer 6.2L gas has better hp/torque output and should be more efficient on fuel economy. However, your empty mpg probably won't be much, if any, better than mine due to the 4.30 gears. So, I would expect the same mpg as my '06 F250 but you will have an easier time pulling the weight. Like the other folks, I would not imagine the Chevy would do much better or worse.