I use a diesel truck as a daily driver as well, and couldn't be happier. I've also towed a 25 ft camper at just over 5k loaded with a half ton and hated the experience. 6 hours to Stone Mountain was all I could take.
Any chance you'll want to get a bigger camper? Regardless, I'd take Barney's advice - gas engine equipped trucks have more payload - which is the number you want to pay more attention to as it will run out before the manufacturers stated tow capacity.
If you buy the truck before the camper, you can always rent a TT from RVShare.com and see what how it performs.
Google - how much can I tow? good luck - keep asking questions and be informed before the purchase!