Towing 39 ft 15.5 k with 1ton Sw diesel - Mistake ??

I just bought a 15 ram 3500 srw with 6.4 hemi. Yup, don't need a diesel. Only tow 10-20x per year. Especially in western ny climate with a 5 mile commute to work. Got the 4.10 gearing. I have a heart land torque 301. It's 15k gvw. The truck pulls it awesome on flats. On the steep hills it works though. It barely moves when loading the fiver (no squatting, just a little movement). I almost made the mistake of buying a triple axle. Maybe some day when I retire.