If you are looking at hauling that much I would go with the dually. Our F-150 worked fine for hauling until we got a two horse slant with a tack room. It pulls it but it has a difficult time of it.
Big trucks are different when you first drive them, but you'll get used to it in no time. However, I don't really think you NEED the dually feature. We turned it down in a new truck because it doesn't really do much for what we use the truck for, which is about the same as you will be using yours for. It also makes taking it common places a lot easier. Duallys are truly a pain in the you-know-what to park!
Big trucks are different when you first drive them, but you'll get used to it in no time. However, I don't really think you NEED the dually feature. We turned it down in a new truck because it doesn't really do much for what we use the truck for, which is about the same as you will be using yours for. It also makes taking it common places a lot easier. Duallys are truly a pain in the you-know-what to park!