As an amatuer historian of the period i should comment that actually the Japs felt that they needed Port Morseby(SP?)in Southern New Guinea as a staging area and port for the invasion of Northern Australia.
An invasion force of troopships escorted by warships including serveral(4?) aircraft carriers set forth for the invasion. Spotted by coast watchers and US submarines, the invasion force was intercepted by US Navy aircraft flying off the Saratoga and Yorktown. One Jap carrier was sunk or severely damaged. another was damaged to the point of being unable to conduct flight operations and the invasion was cancelled. The Saratoga was lost and the Yorktown damaged to the point the Japs thought she was sunk or at least out of the war. Hastily repaired, she was a factor in Midway 6 weeks later.
This was the first naval engagement in which opposing surface forces were never in contact with each other and became known as the Battle of the Coral Sea.
Dugout Doug was not a factor and was likely entertaining media and politicians in Australia. Likewise, the area is so far from Midway that I doubt that any patrol aircraft form there could have provided any information as to Jap formations or movement.
And How could the Japs, their forces obviously stretched to their limit possibly have hoped to occupy such a huge continent with population centers or resources thousands of mile apart?