after just being there, walk away, the durango isn't going to pull it no matter what the book and dealer tell ya. Get a HD, though I will say I just traded in my durango ad bought a 1500 and towed my 27BHS with no issues, didn't even know it was back there and I was a little over 7k with it loaded for the weekend trip. I went through the mountains of NJ, PA and back in CT with no issues, the tranny hit around 205 or so with the outside temp of 93 when I was heading home in CT though I was going uphill for about 20 miles.
Don't even bother with the durango, though nice truck, but can't pull much. Even before I bought the 1500 I hooked it up to my camper and did about a 20 mile test pull and it was loaded for our weekend trip already, and it pulled it so i bought it. And I live in the NW Hills of CT, so I'm going up and down hills both ways.