Well, Purcellville has about 7,000 or so people, a few grocery stores, some restaurants, a nice downtown, etc.
Lovettsville has maybe 800 or so people, and you'd be going to Brunswick for most of your basic needs. It is definitely more isolated. OTOH, Brunswick *does* have a MARC stop, so if you commute into DC, that might work better for you.
I'd want to know your needs for land, privacy, commuting, etc., first.
Why not Leesburg itself?