good thing you asked. i would put the odds on a 6am start to catch an 810 out at 3 out of 4.

go to google maps. type in 22101. select google traffic. this morning, easy trip in hr and a half or so. check again tomorrow., then stay near dca. the taxi line at pm at iad is rotten, but with 16 hrs, you are certain to make it to dca on time. lot of decent restaurants in noVA. if you want restaurant recommendations, what kind of food, and what price? lot of good ethnic in the area.