Abstract: A post-and-beam mechanism easily connectable to a standard car dolly carries on its beams a standard boat trailer, loaded with boat and outboard motor, above the front end of a towed vehicle on the dolly, with the rear, heavy end of the trailer and boat located forward most. A motor home may tow, to the destination site, the dolly thus loaded with towed vehicle, boat trailer, boat and motor. The post-and-beam mechanism is pivotably swingable from a low position for loading the loaded boat trailer thereon; to a high position for carrying the loaded boat trailer. The towing is safely done, with advantageous forward weight distribution of the carried trailer, boat and motor, and with short combined overall length of towing vehicle and towed vehicle, for easy driving and parking. When the destination site is reached, the towed vehicle is unloaded from the car dolly, and the mechanism may be lowered from the high position to the low position for unloading the boat trailer.