Flight
DC is easy to get to from Dulles and BWI as well, but if you don't want to rent a car National is your best option and is accessible via metro (Yellow and Blue lines).
Train
Parking around the venue is quite limited! However it is located on the Yellow and Green lines between Columbia Heights and U Street stations. We highly suggest taking advantage of the local transit, but uber, lyft, and local taxis are also easily available.