Your post is very timely as I am in a very similar situation! I, too, bought a Ram 2500 diesel with the expectation of towing an R-31CB and have been questioning the decision as I've been running the numbers. I can't tell you anything from experience yet, but I can share my thoughts.
The diesel has plenty of power for the job, but my main concern is exceeding the GVWR, which is 10k lbs on the 2500. I took my truck to a Cat Scale and it measured 8200lbs with just me and a full tank of gas (a little heavier than I expected - damn that leather interior!) That gives me 1800 lbs payload to play with. The boat with a little gas and a few accessories will probably weigh 12k lbs. The trailer around 3k lbs. So, assuming the tongue weight is 10%, that adds a payload of 1500 lbs, leaving 300 lbs for my wife, kid, dog, and any additional items. That's getting VERY close to max GVWR! If the tongue weight is closer to 8%, that'll buy me a few hundred more and I'll be more comfortable, though I still sorta wish I'd gone for the 3500.
My game plan going forward is to give it a try. If it doesn't look right or feel right, I'll stop and find another solution (whether it be hiring a driver, renting a bigger truck, or ultimately buying a bigger truck). By the numbers, it should be legal and capable, but you just can't tell until you've got it all hooked up!
I did find a case on the Facebook TugNuts group of someone who towed an R-31CB from Portland to Newport with an F250 and didn't seem to have any issues. Not sure if that truck had airbags or not.
My last big question is - do I need a Class A CDL to do this? The answer seems to hinge on whether or not this counts as a "recreational vehicle".
Hope this helps!