Congrats on making the leap. I don't think you will regret it, especially since you will have a well matched combo.
Since you haven't maxed out the weight capacity of the truck, actually have a pretty good margin, I would wait on any modes until you see how it rides. I think about the only two mods you will want to make is a set of stable loads to help prevent the sag and more importantly a rear anti-sway bar to help with the side-side motion. But these things can definitely wait.
Suggest you weigh the combo on the way home, then again as you leave for your third or fourth trip. You will either pat your self on the back for packing light or shock yourself with how much weight you added.
Again, congrats and happy trails.