i slug everyday, tacketts mill to pentagon works great. i dont know what your schedule is like but im at the slug lot at about 6:30am and get to the pentagon at about 6:50, i get to the pentagon lot at about 4:30 and get home at about 4:50. what you're going to have to figure out is what slug line is closest to the navy yard is actually running, and what are the peak times and where do they go. coming from dale city my guess is you would try to get to the horner rd lot which fills up real quick