By car
The U.S. is an automotive country, and Montgomery County, despite having quite impressive public transport, is no exception. Driving is without a doubt the most convenient way of getting around, but be forewarned that the county has some of, if not the worst traffic in the entire nation it vies for that dubious distinction with neighboring counties in Virginia. The aforementioned north-south arteries, as well as the east-west Beltway and northwesterly I-270 and the Rockville Pike between Bethesda and Rockville are the main routes around the densely populated parts of the county.
By bus
Montgomery County has an excellent bus system, and while it may take you a while to get where you are going, you can reach just about any major destination in the county by bus alone. WMATA's Metrobus (http://wmata.com) has a respectable network of bus routes right in the inner suburbs, while Ride On Bus (http://montgomerycountymd...) is the county bus service, with very comprehensive coverage of the densely populated portion of the county. Note that WMATA's SmarTrip card works for Ride On buses as well as the Metro and Metrobus.