Jump into an F-350, get the camper you want and worry less. I'd skip the whole dually thing unless you want a giant 11 foot, double slide camper. Sure you get six tires and truck that is all but useless for hauling anything but a camper or six horse trailer.
As far as other brands of truck. With a GM or Dodge product their is an actual difference in the equipment between the 3/4ton and the one ton pick-up. A GM/Chevy 3/4 ton truck is an upsized 1/2 ton truck. Dodge is similar.
Ford suspension part numbers are identical for either 250/350 suspension parts, springs and axles. You get a different badge and more weight on the GVWR sticker with a Ford.
More weight means more taxes, fees and higher registration costs over the life of the truck. Check the truck prices, they are shockingly the same on Ford.