Don't worry about the RPM. Unlike many other engines, these do well and are engineered for this type of driving (high load and rpm). Back in Germany, I would drive for three hours from Nurnberg to the south side of Munich at 140mph+ with the foot on the floor. Dad still does it in his Benz with 245,000km on the odo.
As to towing with the Treg/Ceyenne, the best part is having the air suspension because you don't use a WDH. I've posted these elsewhere, but...
2013 Winnebago 2301BH-Red
2012 Ram 2500 Megacab HO CTD