Rockyroads... Here's our experience; hope it helps
(See signi) Our tv does well long distances pulling our 30.5' tt (hitch to bumper) which weighs 6k loaded (hitch runs around 1000-1050lbs depending on what's stored where and how long we plan to be on the road etc.)
We have made several trips cross country and have well over 12,000 miles on our 2 1/2 yr old tt. Some days we did 10hour runs(with breaks) at around 60-65mph.
Issues we have is that our tv slows to about 45 mph (in tow haul) on long mountain grades, or to about 55mph on longer slight hilly terrain. However what's nice is that heading down the grade our tow haul mode keeps us slowed so we don't ride the brakes.
Definitely keep up on maintance and check your tire pressure etc etc as needed. Visitng a CAT scale will give you piece of mind.
Happy travels and have a great trip (don't forget to post pics)