I find driving in DC a breeze compared to NYC and the crowded roads around where I live. Parking is very easy on weekends in the downtown area when all the businesses shut and everyone heads to their homes in MD and VA. If driving, try to plan your visit on a weekend so you won't have to worry about paid parking or scrounging for a space. The Washington Metro is a joy. Clean, efficient, and cheap way to get around DC.
We drove from Chicago but watch out because it is common for hotels to charge $15.00 and up a night for parking.
Taxis were reliable and easy to come by. The public transportation is supposed to be excellent as well but we didn't have the chance to try it.
A 4-hour trip from New York City to Washington, DC seems to be a reasonable for driving your car. But the idea was to get everybody there relaxed, equally. We voted to take the Greyhound/Peter Pan bus from New York’s Port Authority at 42nd St., and 8th Ave. We had also the option of taking the Acela or MetroLiner train, which stationed at 34th St., and 7th Ave., but the fare was too pricey. Yet, trains are faster than buses. Which is why, majority of business travelers prefers the Acela or MetroLiner to get to DC on time. It is not recommended, however, to fly out from NYC to DC. As I understand, the traveling time from the BWI Airport to downtown DC is about 45 minutes and not to mention to LGA Airport in NYC or Newark Airport in New Jersey.
Getting around is always a matter of choices. As for me, to get acquainted with the place I always save my energy for walking. Riding a taxi or metro bus is also an alternative, only if my feet start to complain.
Although it is an old American city, I wouldn't think of getting around without a car. Especially in winter.