All apples to apples other than the differences you posted, while I’d be tempted to go for the low geared 2011, for me the 6 speed and a year newer would be what I’d go for.
More low end oomph with the deeper gears, but neither truck will be towing in OverdrI’ve much if any and the rest of the year you’ll like the 6 speed and highway gears. Both have MDS correct?
BTW don’t let the weight cops scare you too much about the “low payload”. It’s a common theme on here, but with a wdh and/or one of the many available easy suspension mods, the axle and the rest of the truck will do fine with it.