Moreover, if you are originating from DC, why not just take Amtrak to NYC? You can then take the Long Island Railroad directly from NY Penn Station to Jamaica, then the Airtrain to JFK from there. Those are all very easy transfers to make.

I think the train should give you enough comfort to budget far less than a 12 hour layover. If the train is delayed for hours, it's either because of a freak Amtrak problem (5% likelihood) or bad weather (95% likelihood), in which case your flight to Asia probably isn't leaving anyway.

You can use the money you would have spent on a lounge to upgrade to first class on Acela, which will give you plenty of room to work, free food, and all the alcohol you need to dull the pain of your long flight in Y.