It's more like LA to San Jose. I would fly. I'd rather fly than drive 95 by myself, and I agree, one accident and your 4 hour trip can easily be a 6 hour trip. And there's always traffic by Six Flags, even when it's not open...so bizarre. I would return the car in NC, fly to DC, take a cab to the hotel, and rent the car at the hotel if they offer that service.