Towing a Travel Trailer

BTDT with a 1/2 ton. Towed slightly less at 7300lbs loaded and TW of 900lbs. Truck had 1857lb payload. It can be done. But won't be easy. You will need to watch you trucks payload very closely. With a 6400lb dry TT you be around 7400+lbs loaded. Could be more if that's the brochure weight. Ideally you want between 10-15% for tongue weight. 12% is close to 900lbs. Add up everything like who's going with you and what you'll put in the truck. It all can't be more than 1600lbs. And chances are you may not have all that 1600lbs to start with.
So as you can see you're borderline on payload. Power wise with the Hemi shouldn't be the issue. IMO look for something in the 5-5500lb dry weight.