I just finished my 2 week trip to Badlands, SD and the 2500 is much better than the 1500 was towing. The 2500 stayed primarily between 2200-3200 rpms and I could maintain speed pretty well- I only got over 3200 rpm's a few times , not counting merging onto the highway. The 1500 would shift frequently and tended to stay out of overdrive gears. The 2500 was able to pull in 7th a fair bit of time and I could get into 8th if it wasn't windy and I was following a semi.
We had essentially a full day of 20-22 mph crosswinds as we passed the great lakes and it was certainly noticeable and tiring. The truck and trailer were blown as a unit, not swaying from a lack of sway control on the trailer. My truck and trailer crossed the scale a bit over 15,000 pounds. Roughly 4100# front axle and 4700# rear axle and the rest was the camper, which is a Coleman (Dutchman) 2855BH with a 5900# dry weight. For a gasser, the truck did admirably and the 8 speed transmission did very well finding the right gear through everything including up to 9% grades on Route 9 through NH, VT, and NY. I had none of the issues that the 6 speed owners seem to complain about, which is basically the transmission lugging rather than allowing the truck to stay in the power band.
Despite the job well done by the 6.4 powered 2500, I've had enough of a bumper pull trailer and messing with wdh bars and trying to make a long trailer tow better. I'm not sure if the combination of a 9" drop hitch, a wdh hitch, and a nearly 32' long trailer makes it suck but we're looking at a half-ton towable 5W. I want to stay under 10k dry weight as I've heard that much beyond that really taxes a gas engine, especially with the higher profile.