Our travel trailer is almost 34 feet long and 8,000 pounds empty (1,200 pounds tongue weight), which is almost as large as the Grand Design you're considering. We tow it with a 2013 F250 diesel using a Reese Dual Cam hitch. This setup works really well although I did add airbags. Without the bags, the rear end squatter quite a bit and I would hit the bumps stops sometimes. Airbags evened everything out.
You're going to need a Class V hitch to pull that Grand Design, which I imagine is what came with your truck. With the proper WDH and perhaps air bags I think you'll be fine.
I've heard nothing but good things about the Hensley and Propride other than they cost a lot and are more difficult to hook up.