Rockville (route 355) South.  Bear Right onto Woodmont Ave.  Slight Right turn on St Elmo Ave.

Old Georgetown Road (Route 187) South.  Turn Left onto St Elmo Ave.

From Washington DC:

Take Wisconsin Ave. north.  Make a slight Left onto Old Georgetown Rd (Maryland Route 187).  Turn Right onto St Elmo Ave.

From Northern Virginia:

Take the Capital Beltway (I-495) toward Baltimore/Bethesda, Maryland.  Take Exit 36 and merge onto Old Georgetown Road (Maryland Route 187 - Bethesda/Rockville) toward Bethesda.  Turn Left onto St Elmo Ave.