Do you need Commercial Plates in NY to tow a trailer?

No you don't cuz you don' have a high GVW to warrant commercial plates. Plus based one what you said, you don't plan on towing heavy/crazy. Have I seen comm plates on a 1/2 ton? Yes, but the truck have be used for comm biz. With pass plates, you'll be able to traverse roads that comm trucks cannot and MAYBE exact same truck cuz they have comm plates. Here in Syr area, comm trucks/plates banned from a road along Onondaga Lake, BUT a p/u w/ pass/town gov't plates can go on the same road. Go figure.