Thanks MM49 and FishOnOne. MM49, in response to your comment: in difficult terrain, towing even 75% of its capacity, it is not a powerhouse, and in my opinion RV owners using a Ram 2500 as a tow vehicle would be much better off with the Cummins. That info isn't really out there as much as it should be and I'm trying to help other people avoid the situation I am in.
The truck has been to two different dealerships in the past week, both of whom ran and cleared diagnostics. One was in a small exurb of Denver but the other was a large, high volume dealership in the city. The Service Manager got into the truck with me today and he and I drove around in the foothills with the dashboard diagnostic tool engaged and he came to the conclusion that there's nothing wrong with the truck. It's just not as much truck as I anticipated based on what's advertised by the dealerships in connection with this 6.4L HEMI. It's disappointing, I know. Especially since I now own one and can't cheaply get out from under it. Even as a 6-week old trade with less than 4000 miles, I will wind up taking a hit in the ballpark of $5,000 to get into anything else, plus the premium of whatever diesel engine I buy. I'm slated to cross the Rockies about 6 times over the next few months, and I just have to decide how much I want to deal with this.