DART Buses supplement Metro Bus service in Alexandria to various points and historical landmarks within the city and connects with all of Alexandria's metro stations and the Pentagon metro station during weekday rush. Connections outside the city are provided by Metro Bus. The "Dash About" free weekend shuttles are colourful like this one, but the regular buses have a dark violet stripe and goldenrod lettering.
Virginia Railway Express is a commuter train line rather like New Jersey Transit or SEPTA in the Philadelphia area. There are two main VRE lines. One runs from Washington's Union Station (through Alexandria) to Manassas and back. The other runs from Washington to Fredericksburg.
This is a map of Old Town to get you aquainted with the area. Most of the Old Town shops and restaurants are within a few blocks on either side of King Street. Take a nice healthy walk as you go from the King Street metro station to the waterfront and take in the charm of Old Town.
Metro Bus takes you not just all over Alexandria, but all over the Washington, D.C. metro area. It covers the all of the city of Alexandria, the city of Falls Church, Washington, D.C., and parts of Fairfax County, VA; Montgomery and Prince George's County, MD.
King Street is in Alexandria is one of many metro stops in the Washington, DC area. The metro is a convenient way to get from point A to point B.