Zoran: I have used the MARC and Amtrak service to/from BWI/DC more than once without issue, I don't know if that was the plan you were trying, but I will say that the MARC train was super cheap -- not sure if it runs that late at night though.
Those can both get you to Union Station in DC, and the Amtrak can probably take you to Fredericksburg, which is about as close to the lake house as you could get with mass transportation. There might be a better option though.
According to the RSVP list, Trent is flying in to DC pretty late on Monday. Your best bet might be to coordinate with him because your time slots should more or less line up by the time you get from the airport to DC, by whatever means. If you need help contacting him, I think some people here know how to get in touch directly. Whether he is getting a ride or renting a car, I am unsure, but anyone flying in to Dulles is most likely leaving the airport by car.
There are shuttle services from BWI to IAD but I am unfamiliar with cost/timeframe on these options. If you don't really care what it costs, this might be the simplest solution to get you linked up with another person who is going to the same place you are.
However, a lot of the guys who come to this event try to keep the total cost low, if you fall into that category.....To get to IAD from Union Station for cheap takes some effort, no direct rail link. Maybe some kind of meet in the middle location could be most effective, like you could take the metro to Tysons Corner station, which would be a convenient (I think) pickup spot for someone coming in a car from Dulles toward I-95.
Will you have a phone or internet connection to stay in touch in case you have any travel mishaps or delays? Posting directly to this topic is a pretty safe bet if you are ever totally lost with no direct contacts. If you find yourself stranded in the middle of nowhere, someone will come get you as long as we know where you are
