I think taking Washington is possible but holding it is what is almost impossible.If you don�t take eastern United States and central United States or Western United States because if enough us forces are in those territory�s especially tanks they can just roll over you cause the axis are most likely not going to have very many units there cause it�s always just some loose units. the Canadian factory in Quebec can be used to liberate Washington or the uk player can build in London and amphibiously liberate but their is a chance that the axis and capture Ottawa and the Quebec factory if undefended.
US would not have much at all in the west anyway as they mostly build fleet and maby some inf and transports.
Tanks and mechs are pretty useless for the US in the pacific its inf and art you need there. So the US cannot recapture the first round at least. And after that you can land planes and build 3 extra units with the 70+ income it could just be 3 planes as well.
Once you get washington as germany Even if UK can take it back the same round its still a great move. Although if you got 2 transports best take both western and central if you can destroy 2 major factories.