Crystal City is an area near Arlington, VA comprising of businesses & hotels. Crystal City Marriott at Reagan National Airport is very convenient with complimentary shuttle from the airport. While the front desk clerk said that the Metro line was about a two minute walk from the hotel, a previous stay at another hotel led me to ask about connection to the underground mall. Yes, from the Basement level, the hotel connects directly to the mall. If the weather is bad, this is an option that the staff should readily share.
The room was spacious by DC standards but the AC was set very cold. An attempt to set a higher temperature on the thermostat was not successful even after a visit by a staff member.
Considering how sparse affordable parking is available in the city & how efficient the Metro operates, this is a great option to see the attractions around the Mall.

We visited the DC area for a retirement of the friend at the Pentagon. The experience at this Marriott was less than good. The staff was excellent but the facility was not. The heat in our room quit working and we had to change rooms on a Friday night, Needless to say, when you have been on a room for a couple of days and need to move it is not a good experience to pack everything up and move on. The last three days were spent trying to find where things were. Not good and no apology or acknowledgement from management for the extreme inconvenience