Between watching the Redskins win, the Bosox win, and my man Dale Jarret win (how about them apples, Puddin?) I have been working on a time line.
If the teams arrived at the first pit stop between 3 and 5PM on the 8th, they would be leaving between 3 and 5 AM on the 9th This is assuming that the normal and traditional 12 hour mandatory rest period is in effect. It is about a 32 minute drive from the Pit Stop outside Lancaster to the Shoe House in Hallam, PA (that is assuming again that the teams can read a simple map) But we see the teams there in daylight so perhaps we have a typical bunch point waiting for the place to open at 6AM or 7AM. Once they get the clue it is no more than an hour's drive for the 53 miles to Frederick, MD and the Monocacy Battlefield. So they could arrive there by 8 or 9AM. Say it takes two hours to complete the Detour Task then they would be finished by 10 or 11AM. It is another 40 miles to the center of Washington DC but with traffic what it is on Interstate 270 and the infamous Beltway lets say it takes them an hour to make the trip. This would put them at the Capitol location between 11AM and Noon. This matches the shadows we have for the Washington Roadblock task.
I have gut feeling that the line "Drive yourselves to Washington DC" had been lifted and inserted in scene of teams leaving the Shoe House and is typical CBS misdikrection. It does not make sense to drive past Monocacy to Washington and then back to Monocacy. And the shadows seem to be mid morning rather than late afternoon.