From Washington, D.C.:

Rt. 66 (West, toward Front Royal) -OR- 
Dulles Toll Road (Rt. 267) (West, toward Dulles Airport) 
Exit onto Rt. 28 (North, toward Sterling) 
Exit onto Rt 7 (West towards Leesburg) 
Left at Lexington 
Right at Atwater 
Right at Ashbrook Pl 
Right at 20098 Ashbrook Pl into parking area.

From Tyson's Corner:

Rt. 7 (West, for 18 miles towards Leesburg) 
Left at Lexington 
Right at Atwater 
Right at Ashbrook Place 
Right at 20098 Ashbrook Pl into parking area.

Directions in PDF:

Directions to Cizer from Washington DC
Directions to Cizer from Dulles Airport