To be honest, probably not much further. We left Central Jersey at 3:15 AM and made it to Brunswick, GA at 5:30PM. Santee is approx 2 1/2 hours north of Brunswick, and with where you are to where I am, that's approx 1 1/2 to 2 hours more of driving from where we are. Also, since you are farther from me, you'll hit DC closer to rush hour than we did, so you'll probably see more traffic there than we did. We got hit the beltway about 6AM, and hit traffic just before crossing into VA, which delayed us about 20 - 30 minutes. Getting to the beltway 2 hours after that will result in MUCH more traffic, and will delay you more than we were. You might be able to push it another hour or so, but I know after all that driving, we were wiped, and Brunswick was our intended stop so we did push it the last hour. We really should have stopped in Savannah and will next year. We stopped twice only driving down. We ate breakfast and got gas, and then stopped for lunch and also got gas. Both stops probably were a total of 1 1/2 hours, so use that as a guide.