Fly here if you can. Though it is an intimate airport bursting at the seams, and it can be difficult to find flights, it's only a 15 minute cab ride away from D.C. city center. The Metro also serves this airport, and you can take it direct to downtown.
This is the major airport serving the D.C. area and every airline flies to Dulles at pretty much any time of day. It is also about an hour drive from Dulles to downtown D.C. and there is, as yet, no direct public transportation option. There is regular bus service to a Metro line, but that can be unreliable later in the evening. So make sure to price in the cost of a taxi or shuttle bus service with the extra time necessary to make the trip.
Unlike the rest the country, Amtrak runs frequent and timely train service along the north-east corridor from D.C. to Boston. There is also an honest-to-god high speed train that runs from New York to D.C. Union Station (which also connects with the Metro) which is smack in the middle of the city, and a mere 10 minute walk from Congress.
Where to Stay
Congress is on the east side of city center, and you will spend most of your day there. Our training location will be located in D.C. city center as well. Staying in any central location can work well if you are near a Metro station or give yourself plenty of time for a commute.
Washington D.C. can be expensive, and we recommend that you book your stay early. Sites like hotwire.com and priceline.com provide the best deals on hotels as long as you don't care about which brands you stay in. Make sure to limit your hotel search to convenient neighborhoods, we recommend Dupont / Embassy Row, George Washington University, White House / Downtown, Capitol Hill, and Georgetown.
As you might expect, options get cheaper as you go further from D.C. city center. Staying in Arlington or Alexandria can work well, though it's best if you can find hotels near a WMATA line so you can avoid traffic coming into town.
We've used AirBnB many times, and you can find good deals, though the quality of the experience can vary. Make sure to read through the past user reviews and consider your location carefully when selecting this option.
Traffic in D.C. ranges from poor to nightmarish. Avoid driving during rush hours if you can. In fact, we recommend avoiding driving your own car all together. Within the city there are plenty of options for taxis. Lyft and Uber rideshare services are also plentiful. Street traffic in the city is congested throughout the day, and you should give yourself plenty of time to get around to accommodate any potential traffic, construction, or armored car detail for some high-ranking politician.
Take the metro. It's easy. It's cheap (fares start around $2). And it's usually reliable. Do note that the Washington D.C. Metro system (WMATA) is one of the busiest in the nation, and it can struggle to handle demand at peak hours. These peaks are normally during the morning and evening rush hour, where trains will be packed to the brim with riders. Google Maps will provide you transit directions using the Metro that is pretty reliable, and always give yourself some buffer when getting around.