LOVE the 29 route.
Went to the AMA races on the first run there in 2001...drove down Friday after work to camp for the weekend. Spent FOUR hours in the Alexandria mixing bowl south of DC..never again.
MD 29 South hits 495W, to 66W to 29South works just great for me.
And as far as Saturday goes..you'll want to leave Friday night after work.
You could probably get up at like midnight and drive down..but really..do you want to be on a racetrack unrested and not at your best when it comes to being mentally focused when you need to be focused the most?