Hmmm.
A1: Build 1 Carrier, 2 Transports, 1 Bomber, move fleets to Sea Zones 56 and 20
A2: Build 4 Bombers, move Fleet to Sea Zone 46, along with Australians. Land Bombers in Austr
At end of A2, your forces are as follows:
Solomon Islands: 2 Carriers, 4 Fighters, 2 Destroyers, 2 Transports, 4 Infantry
Australia: 1 Transport, 1 Destroyer, 3 Bombers, 3 Infantry, 1 Artillery
Western US: 4 Bombers
Sea Zone 44: 1 Destroyer, 1 Transport, 1 Infantry, 1 Artillery (or they can go for Africa if they wish)
At this point, you have a solid force in Solomon Islands, capable of threatening Japanese holdings heavily, and a flight of Bombers that will wreck the Japanese fleet if they attack you at Solomons, as well as punishing unwary transports.
Not to mention, if they built an IC in East Indies J2, you have a pretty good chance of taking it, especially if you landed Bombers in Australia, though in that case, the British Transport might want to stay home so that the full 4 Australian units are there to guard the aircraft.