Okay, I'll sound like a fanboy for a bit. Of course, this thread is asking for us to come out! ;) I seriously doubt you'll find an owner with anything less than stellar comments.
We just returned from 6k miles going from the east coast, through the southwest and up through the Rockies. We crossed the continental divide 3-4 times and had many, long, serious grades.
The towing experience was better than I could have hoped for when making the purchase. Hearing testimony on the forum that it "tows well" probably still leaves you with doubt...it did me. But I'm here to tell you that it will tow EFFORTLESSLY within its designed parameters. For most of the trip, I set the cruise and could join in the family banter without ever considering the hills (mountains) in front of me. It was that good. I didn't, but am sure I could have jumped in the passing lane on a 6% grade and quickly overtook the cars in front of me. When the roads are just rolling hills, I can tow at 1600rpm (like the earlier picture shows).
In 6k miles, I averaged 11.5mpg. For the last 1100 miles from Wichita to South Carolina, I got 12.1 mpg! I didn't expect it, and was very pleased.
I don't have the HD payload package. Would have preferred to have it, but not necessary for my purposes. I was packed with a family of 4 for 40 days with all the associated junk. It was stable the entire trip (although I'm much lighter in tongue weight than you are).