Is
THIS Your TT? If so, it doesn't weigh 4500 lbs, especially on a cross country trip with all your stuff in it.
To do this correctly, you should load it up and take it to a
CAT Scale and weigh it. Tongue weight is important as it subtracts from your tow vehicle's payload, as does everything else loaded in the TV. I'm betting the tongue weight will be in the range of 600 - 800 lbs.
Please don't shop for a TV based on it's towing capacity. A diesel 1500 has limited payload capacity due to the heavy engine.
If it was me, I'd want a little overkill to drive around the country.
Good luck!