That Ram will be quite capable. What is the gear ratio? 3:55 is OK, but the 3:92 is better. If you can do without the 20 inch rims, the 17 inch version will usually tow a little more and be much cheaper when it comes to replacing tires. The factory brake controller is also amazing.
I am towing a 5500 lbs trailer, with a little higher of a tongue weight, 736 lbs, due to it's design. I have 3:55 gears and they suit me fine, there is some gear hunting on the highway, but keeping it on tow/haul mode locked in 4th gear it is fine. The HEMI really makes the difference, avoid the 4.7 motor.
Good luck!