I'd recommend Googling 'Operation Hulu' & related ops & what they were providing support for.
1. Project Hula, not Operation Hulu
2. The amount of shipping capacity received was barely enough to transport 9,100 men. That is enough to take the Kuriles, but not attack Hokkaido, let alone Honshu. The US was not going to let the Soviets get at Japan proper willingly, especially not with Truman as President.