If you are person that feels that they have to be within all of the manufacturers numbers even though they are not legally binding to you and are only for the manufacturer to be within outdated US highway truck classes and emissions regulations, then get the 1 ton. If you are not one of these types and have enough common sense and experience to not need stickers like "Do not touch engine fan while engine is on", then any of the current 3/4 tons(which are terms that are outdated as the truck classes) will be fine for a 14k trailer.
I have been pulling a 5th wheel around that weight since I bought my truck new in 2014. I have never felt unsafe, unstable, or any of the other things that these weight police alarmist are telling you what will happen. It only squatted about .5 inch more than a family members 3500 of the same model which is about right seeing that my rear axle weight rating was only 500 lbs less than his while my front axle rating was exactly the same.