I'd keep the 2,500. Payload was the reason why I upgraded, with future designs on getting an RV of some sort. I had a 2010 F-150 but then I kept weighing it down with soil, sand, bricks, and other stuff. I figure'd I should do something before I break something.
Since I have nearly the same truck, here's what I did to smooth out my ride. Drop the fronts to 55psi. I'm getting perfectly even tire wear on my truck at this pressure. Heck, as suggested earlier you may be able to drop this a little more and ride comfortably but I'm not sure if that'd trigger your TPMS system. Drop your rears to 45psi. You should be good there as well. Also, your 2500 should have a button for "Light Load". Make sure that's turned on so you don't get a TPMS warning. My truck "Almost" rides as smooth as my F-150 did with Bilstein 5100's all around and LT truck tires equipped. Try these free fixes first before making a decision to trade-down... only to find you may need to trade back up again.
