Your schedule sounds good. Leave Tysons Corner at 5:30am. You'll be in the Economy Lot by 5:50am. Shuttle bus should have you at the Main Terminal by 6:15am. Enter the Main Terminal at the first accessible entrance (west end); go up the escalator; ahead and to the right is Virgin America's ticket counter.

After checking bags, TSA security entrance is at the top of the escalator you used a few minutes earlier. Immediately after TSA security, take the shuttle going to the B60s-B70s gates (shuttle runs every 5-7 minutes). When you exit the shuttle at the B Concourse, Virgin America's gates are immediately to your left. There are numerous options for something to eat in that immediate area.

TSA security can be fairly busy around 6:30am, but it shouldn't take more than 10 minutes or so. I think you should be at the gate by a few minutes after 7:00am.

Have a safe trip.