I'm a down-to-earth, real world, tell you like it is guy. A half ton can carry the thing. I've carried bigger ones on half tons. But it's gonna suck compared to a 2500 or 3500. It will feel more top heavy and nervous, it won't have the heavy duty drivetrain and suspension, it'll feel like it's working hard all the time instead of feeling like its nothing, just easy cruising. The 1500 isn't gonna get better MPG under a load either.
That makes a big fatigue and stress difference on long drives like you're talking about.
Carrying a camper on a half ton is what you do when you already own the wimpy truck and you're stuck with it and then you get a camper.
There's just no reason to go buy the wrong truck now while you have the choice.