When I lived in Manassas, me and several other guys used to ride in an area on the north-west corner of the intersection of Hwy 234 and I-95. You used to be able to park behind the gas station and go thru a couple of holes in the fence. I also rode at an area once that was really cool, it was west of Manassas on I-66 just south of Front Royal. I can't remember the name of it, but it was a legal area part of the national forest area. Living there was definetly a bummer as far as riding areas go compared to being back in Texas!