Theodore Roosevelt Island is located just across the Potomac River from downtown Washington DC. This is probably one of the best park and bike locations due to it's close proximity to most major bike paths. However, there are a few issues with location. First, you can only access it from the northbound side of the George Washington Parkway. Thus, if you approach from the north via the parkway, you will need to navigate the somewhat intimidating traffic circle at the head of the Memorial Bridge. Second, the lot is very popular and fills up fast on nice weekends. Thus, plan to arrive early if you wish to get a spot on weekends. Finally, there is a relatively short parking time limit of only two or three hours. I suspect this limit is in place to prevent commuter parking, as I have never seen it enforced on afternoons or weekends.
1. Cross the TR: Leave the parking lot heading south on the Mount Vernon Trail. Once you reach the boardwalk, continue straight following the ramp up the hill. Cross over the Potomac River on the Teddy Roosevelt Bridge. On the other side of the river, keep following the bike path to the north end of the Kennedy Center.
2. Left on F: At the north end of the Kennedy Center, make a left turn at the cross walk, and then follow F Street down hill toward the river. At the bottom of the hill, cross the Rock Creek Parkway to access the bike trail.
3. Left on Trail: After crossing the Parkway, turn left on the trail and follow the river untill you reach the Lincoln Memoral Circle. Follow the circuit counter-clockwise until you reach the National Mall