Steve,
In one of your earlier posts you mentioned that you should be at the track Friday evening around 5:30, which would have you coming through the 270 exchange around 3. You should be slightly ahead of any rush hour traffic. Stack'd-n-Jack'd will probably hit a little more than you since he will be coming through around 4.
Now I'm not trying to scare you guys into taking another route, I was just trying to give you a "head's up" on what to expect. I work up here in DC, so I am in the traffic every day. If the traffic is not all snarled up, it will be rolling, and I mean rolling. I do 80, and have to get out of the fast lane cause I am to slow.
It's either gonna be good, or bad, not really much in between. Either way I would stick with 270, it's the best way unless there is a wreck. Then everything is out the window.
Your next problem area will be exiting the 495 Beltway onto Rt 5/Branch Ave South, exit 7B. The exit curves around to the right, kind of sharp so watch yourself, then it turns into the on ramp for the 495 North, so you have one lane for all the people getting off, and all the people trying to get on the Beltway. Might be easier (this is the way I go usually) it only takes a couple minutes longer. Take the Rt 5 / Branch Av North exit, exit 7A, stay to the left, turn left at the light, then left at the next light. This puts you on the same road, but you get to use the stop lights to get on to it. Then traffic should be okay, just thick, all the way through Waldorf till the La Plata area, then it should ease up some. Any question, don't hesitate to ask, I'll do what I can to help.
Ted