There're lots of concerns regarding the 2500's coil spring, most are based on hearsay "nothing but a grocery getter!" Let's not forget armored HMMWVs weight 12,000 lbs and are coil sprung. Many heavy missile trucks use coils. There's nothing inherently weak about a coil spring - I can design one that'll support a nuclear reactor.
Enough talk, I'd like to share some real world data on just how good the coil sprung 2500's payload is. The following images are from "ib516" on RV.net. I consider him one of the pioneers of the coil sprung, 6.4L 2500, that wasn't afraid of using it as intended: hauling a heavy 5th wheel with heavy pin weight.
He hitched up a 40' 5th wheel, with ~2500 lbs pin weight, on both a leaf sprung 3500, and his own 2500, and measure the suspension droop.
3500 SRW Cummins, 42.75" unloaded height:
Loaded height, 40.25" sag: 2.50"
2500 6.4 Hemi, 43.25" unloaded height:
Loaded height, 40.75" sag is, SURPRISE! 2.50"
What this shows is contrary to popular belief, or assumption, the coil sprung 2500 is a highly capable truck. It offers payload greater than pre-2014 leaf sprung 2500, and does it with better ride and handling.
Does it have its limit? Of course, I'm sure if you put 4000 lbs in the bed, it'll sag drastically more than the 3500. But that's well outside of its designed payload (3000 lbs).
NorCalHawk, do you intend on carrying additional gear past the 2000 lbs camper? Dirt bike, motorcycle, heavy armor and winch, heavy water loads, etc? If so, and you feel you'll be approaching the 3000 lbs payload, then by all means, a 3500 may be a better choice.
Otherwise, if you think your total load is closer to 2500 lbs like the 5th wheel above, then for all intended purposes a 3500 and 2500 have similar amounts of suspension sag. Hope that helps!
