I have a 2011 Ram 1500 with the outdoorsman package. It has 3.92 gears and a heavy duty trans cooler. If you have the factory hitch it is a class IV hitch and yes it will sag a little but if you have a weight distribution hitch you will be fine. I have WD hitch and tow my shasta revere that is around 7000lbs also and 30ft long. I can barely tell its back there.
My only concern is that you have the 3.92 gears because with the 3.55 gear the towing capacity goes way down it is 8500lbs with the 3.55 gear. I think you will be better of than the armada either way but make sure you are within the limits of your tow vehicle. Oh and if you dont know the rear gear you can contact a dodge dealer and they can run your vin to tell you exactly what you have.
Happy camping!!