You are absolutely correct in your analysis. Same is true for the Chev 1500
w/Max Tow package.
Problem with both of these trucks for us RVers is, we have a tendency to add toys as time goes on. RAWR will, sooner or later, be a concern for you, IMHO. I considered a 1500
Maxtow until I ran over the scales with a regular 1/2 ton truck. Rear axle was the problem.
You're right about the GCWR...you'll always be fine with the powertrain and brakes.
IMO, these two trucks are fine for boaters who have a completely different weight distribution formula. I am just worried that in a couple of years, unless you are very careful, you will wind up accumulating more stuff like the rest of us do. One day you'll decide to run over the scales and you will be shocked at your weight gain.
It think it'll take a lot of discipline to stay under the RAWR.