Question regarding heating toy hauler while towing

Thanks Old-Biscuit My hauler is a work and play without slide outs. As for the heat there are only two registers and neither will be blocked. Like I said. THe only reason Im even thinking about heating is it will be late when we get there and didn't want it too cold but in thinking about it, it don't take long to warm up, and we could just put another blanket on the bed. It was just a thought. I know the dog would be fine, hell I would ride back there if I could get the wife to drive the truck.