'15 Silverado 2500HD 6.0l Long trip

[cybergoon]

I am getting ready to take about a 1200 mile trip pulling my 38.5' 5th wheel camper. I am currently running the standard diablo tune in my truck with DoD disabled. I'm wondering if that's my best bet or if I should make any modifications before heading out on this trip. So far, I have been getting about 7.5-8mpg while towing my camper. Even if I could squeeze another mile per gallon, I'd be excited. Any ideas would be greatly appreciated.

Also, if it helps, I'm going to be travelling from Cedar Rapids, Iowa to somewhere in the UP of Michigan.