Welcome to the forum!
We towed a Rockwood 2605 with a Ram 1500 QC 5.7...the 2603 is similair weight/length and should be no problem towing with the 1500HD. Suggest you get a good WD hitch with sway control.
I'm assuming this is a used trailer as I don't see the floorplan listed on FR's site.
We originally looked at the 2603 before we purchased the 2605. We bought the 2605 because of the huge wardrobe and with the rear kitchen/front storage its easier to balance the tongue weight of the trailer. The 2603 is a mid kitchen/rear bedroom (storage) trailer. Of note, depending on the year, some of these campers will be 7.5' wide or 8' wide (starting in late 2008).
Nights camped in 2013 - 55, 2014 - 105, 2015 - 63