Skipping all the slow-f..k of Central Pacific islands and going to capture Minamitorishima (Marcus Island) soon after Battle of Midway. High risk=High return
The island is just large enough to support B-29 landing, and Tokyo is within the range of both B-17 and P-38 based on the island. Of course, it is also within range of A6M "Zero" from central Japan. But island offer over 1km2 area (equal to ~100 aircraft carriers) for guns placement, and US already had a radar proximity fuses in 1942. The losses will be terrible on the both sides, but the Pacific war can be finished in spring of 1943 by the direct assault of ruins of Tokyo.
That is a definite game changer.
What were the Japanese defenses on the island?
Are the Americans organised for this in June 1942? Guadalcanal in August was called operation shoestring. Can the first marine division take Marcus island in September (will need another month to organize).
So in this scenario, the USA lets Japan take Guadalcanal and build up an airbase while the USA takes Marcus.
Maybe it could work. The USA could raid the Guadalcanal field, make it in-operational and set up B-24 bomber bases on Marcus.
USA would not have the attrition value that Guadalcanal came to be against the Japanese forces. But this is offset by being able to bomb Tokyo sooner.
Perhaps a POD would be a more successful Midway where Hiryu is hit without launching aircraft that attacked Yorktown. So Yorktown is saved. Yorktown would then simply be used as a ferry service to initially send F4F Wildcats or perhaps P-40's (I do not know if P-38's can take off from a carrier)to the island to defend once taken. In this role, Yorktown is still useful, does not need the massive repairs and upgrades.
Australia would howl some, but if it is able to reach Japan sooner ...... awesome
Edit: it would be a bold move. One that the Japanese would not expect. Is Tokyo really in range for B-24 bombers? I do not think that it is for P-38's. Marcus Island could be the stepping stone to Iwo Jima which is definitely in range for B-24's and land based air cover. More of Japan can be mined, shipping taken out.
Wikipedia says that Tokyo is 1148 miles from Marcus. Wikipedia also has the combat range of the B-24 as 2100 miles. It would be at the maximum range, lighter bomb loads more fuel could be used. But Tokyo is in reach. Tokyo harbor is definitely in reach to mine.
So the trade off would be Marcus Island for Guadalcanal.