Ballston, VA to Bethesda, MD
Take the East Custis trail from MaryMount University, Ballston, until Key Bridge. Cross Key bridge into Georgetown. Go East on M street until you come to a bridge that goes over Rock Creek Pkwy. Just before the bridge there is path that leads to the Rock Creek bike path. Head north on the bike path that goes along a creek, through the National Zoo. At Beach Dr. you can cruse on the road because it is closed to vehicles on weekends and holidays. Follow Beach Dr until you hit the Georgetown trail that brings you to Bethesda where you will join the Capital Crescent Trail. The Capital Crescent trail eventually joins the C&O canal bike path. Head South until you get to Georgetown. Get back to Key bridge into Virginia and the Custis Trail. This trail is fascinating all round the year, particularly the day after a heavy rain; you will see the creek flowing rapidly and you will hear the roar of the water all along. Its a peaceful trail, except for the Capital Crescent part where it can get crowded by late morning.