4000lbs + on the back of a 2007 short bed Ram 2500 for quite a few years, and 20k miles of hauling.
It was alot of camper for that truck, but the truck handled it fine. 3600-4000lbs tires depending what tires were on the truck. Home made stable loads, airbags and a sway bar. Not totally ideal, but worked well enough from WA to AK to WI and points in between.
I'd have no issue with what you're proposing. Just know that you'll have more body roll than a dually.
For the ultimate srw setup, add springs vs airbags and some 19.5s. I never did, because 300+ days a year that would have been totally overkill for the truck when not hauling the camper.