I'll be the first one to admit over the years I've towed a big, heavy trailers with half tons.
I did so safely because I weighed my set ups on CAT scales and I knew what my unloaded and loaded axle weights were. I adjusted to return as much of the unloaded front axle weight as I could to that front axle for a safe and stable tow.
However, I was close to and over rear axle weight limits at times and I knew that was really pushing it. On long grades my truck heated up, 215-230 degrees and that wasn't good.
So its ultimately up to you. You bought the 2500 in the first place as you said because you knew with a 35' plus rig you needed one. You've been at this awhile per your post so you know you gotta pay to play.
Current truck and trailer or smaller trailer/half ton are your options. Even if you were within GRAWR, I still would not want to tow a sail that long behind a half ton. But that's just me.
As a former LEO, I've seen too many horrible/catastrophic accidents and what happens in the blink of an eye when things go wrong. Things I wish I could forget.
So I prefer more margin than most. That's why I have a fuel guzzling 2500HD and I love it. No desire to go back to a half ton, but I dont drive it much and I have a rav4 as a spare so I do understand your thought proccess and that different folks have different needs and priorities. Good luck.