I have a 3500 Express (Always have van for towing) - Used to tow a 6000? lb TT - did quite well; Lots of grunt from the V8 - stout transmission and brakes - the long wheelbase help with stability.
I had to add the hitch, Tekonsha controller and 7-pin connector-
I currently have 4,000 lb TH - it's hard to tell that the trailer is back there;
Personally I love vans as you can take all the toys and keep them under lock and key.
Gerry