This region of Maryland contains both its capital, Annapolis and its most populous city, Baltimore.
Baltimore-Washington International Airport (IATA: BWI) is a major point of entry to the region, with the Southwest Airlines hub providing a lot of cheap flights from all over the country.
The big highway running north-south is I-95, which runs up from D.C., past BWI, through Baltimore, and then up the coast through all the major East Coast cities.
Other important routes include I-70, which goes into Baltimore from Western Maryland; I-83, which runs north from Baltimore to York, Pennsylvania; I-97 between Baltimore and Annapolis; and US-50, connecting Annapolis to D.C.
Amtrak is the major operator on the East Coast, and the Northeast Corridor, which runs between D.C. and New York, crosses the region, with notable stops (from south to north) at New Carrollton, BWI Airport, Baltimore, and Aberdeen.
The MARC trains provide a light rail service between D.C. and the Delaware border, passing through the same stations as Amtrak, but with a few more stops, and lower passenger fares.
Sights in Central Maryland are concentrated in Baltimore and Annapolis. The biggest attractions are likely the Inner Harbor and the National Aquarium, the Annapolis State Capitol building, the Naval Academy (also in Annapolis), and more generally the Chesapeake Bay. There are plenty of other interesting attractions off the beaten path, though, like the National Cryptologic Museum in Fort Meade.
The most problematic city in this area is definitely Baltimore, but there are small steps one can take to reduce the chance of trouble.