All of the newer trucks are pretty tall and there are so many spring, block, drive type, tire size, and other considerations that you really will have to see in person. Fortunately, there's quite a range of heights where you'll be able to tow, even if it's not ideal.
I'm in somewhat the same position. I'm going to lower my truck about 2 inches, which should help, but I'd also like some additional bed rail clearance. I am hoping to avoid flipping the axles because fifth wheels are already boxy and tall enough, but that may end up being the solution for me.
Is your truck 4wd? Are there blocks in the rear under the leaf springs and above the axle?