Will be in New York in mid December. Thinking about a day trip to Washington. Any thoughts or comments on this particular journey or any other suitable day trips appreciated.
Thanks in anticipation
Would also recommend more than a day, although no more than two or three. The Smithsonian Air and Space is at least half a day, there are other Smithsonian museums worth seeing and the points of national interest are quite spread out and need quite a bit of walking. You could see the main "sights" in a day on foot but that's about it.
Also would say if on a budget that Acela isn't worth it. It only carries business class and first class accommodation - business being the top class on the NE Regional - so it is more expensive. The top speed is only 135mph (average 82) and the journey saving small. Having said that, Acela is a great train and I use them up the East Coast quite regularly. Excellent cafe bar and the $79 first class supplement gets you food and drink and comfortable 3 abreast seating, if you want to splash out. They're heavily overengineered for overly stringent crash regulations, so need over 12,000 hp for each six coach train!
Weekdays are sometimes cheaper than weekends, and business is sometimes cheaper than coach... but the pricing on the Amtrak website is quite straightforward and transparent. Trains run late at night and early morning too, which may maximise your time.
Megabus and Bolt Bus go to DC but really, although $25 is a good price, you wouldn't catch me sitting on one for 5 hours
In terms of general advice, I'd say there's plenty to see in New York alone, so stick around here unless its a long trip. The commuter lines out of the city aren't really worth a trip, unless you want to try a NJ Transit or LIRR double decker. The NYC Transit Museum in Brooklyn, in what was Court St station, is an excellent way to spend an afternoon