Is there a particular reason that you're focused on South Riding? I lived there years ago and now live further north in Ashburn which I really prefer -- I wish I just started out here in the first place. The access to Rt 7 etc as the PP mentioned is great, I really prefer it to being along 50. The neighborhoods in Ashburn are super nice, with mature trees, trails, all the amenities, extremely family-friendly, etc. From south to north check out Broadlands, Ashburn Farm, and Ashburn Village.