The whole Metro system has escalators and elevators; so long as you stand on the right side of escalators you shouldn't have a problem with bags.

Metro access is at at the western (B. Dalton) end of the station one floor below the main level of the station. Any escalator down will get you to the lower level, then just follow the signs to Metro.

Take the Red Line to Shady Grove (or Grosvenor-Strathmore) two stops to Gallery Place/Chinatown. Turn right as you exit the train and go downstairs to the lower platform. From there you will catch the Yellow Line to Huntington; Crystal City is the fifth stop, the third after the bridge.

During rush hour the trip does not take long at all, under half an hour. The trick is that offpeak you may wait a while for either train, as much as 20 minutes at Gallery Place. You can use http://rideguide.wmata.com/ to get a bearing, but keep in mind that it is only an estimate.

Metro accepts Visa, Mastercard, and Discover as well as some ATM cards. If you want a a pass you need to use the "Passes/Farecards" machines, usually located on the ends; any machine will do for a regular farecard.