I have a 24' 77 Argosy Rear Door model and I tow with a 8,000lb WD Reese hitch with 12,000lb ball, anti-sway bars and no brake controller, although I am having the wiring installed this spring and already have the brake controller. We did a couple thousand miles last fall and my Suv is a 2004 Mercury Mountaineer with newly installed hitch, no towing package but rated to tow 7700 lbs. 3500 w/o new hitch.
We did grades up and down mountains and had zero problems stopping or going, other than needed some grate clips for the stove top
. From the info we found, our Argosy weighs approx. 3260, and 3800-4k with our stuff in it. We have no awning or AC so that might take the weight up a bit when and if we get those items. I think you will be fine as my Mountaineer is a 4.6L V8 AWD and does not weigh much more than the trailer. (4300lbs)
Also wanted to point out that we took our trailer to Airstream factory service center and its original
axles and newer bearings and tires were deemed worthy of the road. So please do not automagically assume that old axles are bad. Ask for Wayne at Airstream, he is the Vintage Specialist, in our opinion.
He will go above and beyond to make sure your trailer is fit and safe and will imagineer a solution if he finds a problem you might not have even have known about.
And his advice about how to do the rest yourself is invaluable.