Depends if you are going down on Thursday or Friday. The exodus from DC on Fridays starts early, sometimes traffic gets heavy (heavier) as early as 1 pm. Thursday is a bit better but if you have my luck it also can be a pain.
Where in PA are you starting from?
Depending on where you start from . . . alternatives include Route 15 south past Gettysburg down through Maryland to Frederick, MD
or take 95 to Baltimore and then I-70 to Frederick. Signs and ramps getting to 15 west out of Frederick can be a bit tricky. Make sure your navigator is awake.
From Frederick take Route 15 out to Point of Rocks crossing the Potomac and down through Leesburg, VA picking up 17 south at Warrenton, VA. Some 2 lane stretches in Virginia but generally moves well and suitable for trailering all the way.
The crap shoot with doing DC / 95 / 495 is if traffic stops IT STOPS and you are stuck forever
If you go early on Friday you can get stuck with the morning rush which can last till 9:30 or later.
If you can get away on Thursday I'd suggest it and then you can be at the track all day Friday, get signed in, teched and help set up the course.
Other Warnings - It is now a crime to Text while driving in Maryland. Also Maryland is now using photo radar in construction areas. In Virginia - Radar Detectors are illegal.
Hopefully I'll see you there. Haven't made it to a meet yet this year and am suffering major LSR withdrawl . . .