Walk around and do some shopping at many of the boutiques, home goods and antique stores in historic downtown Leesburg. If you are looking for something to eat, Market Station is a good place to start with quite a variety of places to choose from. There are even more cafes and restaurants as you walk through downtown. There are also many restaurants in walking distance of the block hotels, including a burger place ranked in the top 10 burgers in the US according to TripAdvisory--Melt. We can tell you it is one of the best burgers we've had in the area.
Loudoun county has many beautiful wineries to try. Stone Tower is located just minutes down the road from Oatlands.
Stop in for a wine slushy and a pizza, or just grab a glass of wine and enjoy the outdoors. There is also a brewery on the property and can do a flight of beer instead, if wine isn't your thing, or do both!
Another winery located in Leesburg where you can relax and do some wine tastings.
The ground floor of the house will be open for guests after the ceremony, but you can visit the house and tour the museum upstairs with paid admission.
Also a historic house, the park is free to enter but tickets can be purchased for a mansion tour.
Washington, DC is only about an hours drive east of Leesburg. If you don't want to drive in, the Wiehle-Reston East Metro stop on the silver line is about a 25 minute drive and you can ride the train in (they will be performing maintenance through 2017 so you may want to check the schedule for closures and disruptions). You can spend the day walking around the monuments, touring museums and eating great food.
If wineries aren't your thing, there are a number of craft breweries in the area. Crooked Run is located in downtown Leesburg.
A good craft brewery located between Leesburg and Dulles airport.
Also another good brewery outside of Leesburg.
Drive through the Shenandoah State Park on the 105 mile road system that provides beautiful views of the Appalachian Mountains. Tickets are good for unlimited entries for 7 days. The entrance in Front Royal is about an hours drive west of Leesburg.
The public park has several hiking trails, campgrounds as well as a water park inside! There is an entrance fee per car for anyone not in the northern Virginia jurisdiction and additional admission fees for the water park. Other NOVA parks have boat rentals as well.
For anyone who likes to golf, Bull Run is a public golf course down the road from Oatlands.
If you just want to hit a few golf balls, a new Topgolf has opened in nearby Ashburn.
Stop by the air and space museum without going into DC. It has many military and recreational planes from over the years, as well as a room dedicated to crafts used for space exploration. This museum is just minutes from Dulles airport.