Newbie Checkin! - New to Forum

Tuning for economy. Welcome!

From the look of your pics you travel in style! As to fuel economy gains? Your biggest enemy is your aerodynamics and weight! But if you think of it pound for pound the same truck thats gas would do no better! I agree on the use of a smarty. But; it will only help you in the lower end. Once again; you will have to wait till after the warranty expires. There are some mods that dealers will allow provided they instal them.
If you go with a smarty or any variant, you might not see to much of a gain. the only way to experience this is through intake and exhaust upgrades. You can piggy back the smarty with a H&S to have the best top and bottom end power. This could be over kill for you and you might be lost already (I tend to do that, sorry). But it is what it is. in order to see good gains you have to build your rig to suit your needs.
Whats your final gearing? That could be a contributing factor to fuel economy. Going to 3.73-3.55 will help and keep it towing. it will just take longer to get to speed, you're in no hurry right? Driving habits/conditions, transmission, tires all make the difference in your goal to economy and hp gains. You may want to keep your truck stock and just do a mild tune, gauges, intake, exhaust, and programer.
With that said