I think you right to have United States go to Pacific in game. United States with full Pacific fleet, Japan buy no more ship, Japan lock in spend at least 18 IPC on land unit for Industrial Complex, and Japan lose 2 of 6 Fighter means good time to go Pacific.
United States start to take Islands quickly in that game even with 2 Battleship and 2 Aircraft Carrier for Japan. He only have 1 big fight with fleet before he no longer have ship force in Pacific.
United Kingdom will have much work to do. Will have to send land unit to Norway and to Algeria going back and forth each turn to hold Africa and keep Germany from focus on Russia.
I think game you describe would be fun game to play.