I do apprecite the concern, but I definitely considered weight when buying. We really preferred a Jayco Jay Flight in the same floorplan, but it weighed 1000lbs more (being wood framed vs aluminum framed). I knew that might be pushing it when loaded, so we went the Premier route.
I think with also 3000 lbs of difference I am well covered. I never tow with the tanks full (except within a campground to the dump stations for example), and we don't load it up. Checking my old trailer we carry around 1129-1272 lbs of cargo (scale based). We haven't added anything more for cargo to this rig, so I have nearly 2,000 lbs between my rig and the truck's capacity.