I'll be going to reston on the 27th. arriving late in the evening, and leaving the next day at night. my stay is only 24hrs (because of work). and it's my first time there so i'm thinking of renting a car so at least i can see the city and nearby cities in my short stay. but i need advice because there might be good transportation system so i might just be wasting money on the car rental. i'm also thinking of visiting a cousin in Williamsburg. please help! thank you so much!!