a 2 bedroom apt near where I live often goes for the staggering sum of 1600 dollars a month (or more!)
Out in Mclean things can be cheaper, my buddy Mike lived in Reston in a 2 BR apt for 1200.
Driving will be key, if you live outside the beltway, you'll find public transportation is spotty or just downright bad. However if you slug like E you can get rides almost anywhere (though more typically you'll get Springfield commuters) Slug lines rock because its organized accepted hitchhiking to allow drivers to use the HOV lanes (and thus avoid traffic) again, out by Mclean you'll have less of that. What you will have is a quieter community, and a little more nature... plus you'll be close to Wolftrap (an outdoor stage where tons of concerts are given in the warm months) tickets range from 15 dollars for lawn seats to 75 for nice cushy box seats.
Getting into DC is easy, just drive to one of the large metro stations, and take the metro in. For a small outlay you can get an all day pass, or a monthy pass. Once in DC you have a nice Zoo, the Smithsonian Museum complex, major league basketball, football, baseball teams, amazing shopping, heck theres even an anarchist soccer league that doesnt mind who shows up for pickup games. We have a small chinatown, and some great dining and tickets to events at the Kennedy Center are usually inexpensive. Plus you have the National Gallery of Art, the Corchoran Gallery, the Gugenheim, and the National Cathedral. Baltimore is an hour and a half away so there you have more football and baseball, the historic inner harbor and the aquarium. And the Md State Capital Annapolis is neat because of the Naval Academy.
As for parks you have several.
The big national park in VA is the Appalachian Trail a 2000 mile trail that runs from Georgia to Maine That cuts the state in two. A person up for a day trip can drive out to the penninsula to check out Chincoteague and Assateague (where the wild ponies live) or drive down to Williamsburg and Yorktown.
Shorter Daytrips bring you to almost 30 civil war battlefields, Mount Vernon, and the Maryland Renfest (In August and September)
Come see an indie film in Shirlington or just drive down route 17 and get yourself an old time frozen custard. Or drive west in the Shenedoah valley to pick apples in the fall or canoe, kayak and whitewater raft in the spring and summer. Drive out to Winchester for some nice antiques (or Manassas or Fredricksburg) or go shopping at the Potomac Mills Outlet mall. Or my personal favorite, drive to Old town Alexandria in the Summer and walk down King street.
Its fab..