As the mom of a two year old (and another on the way), living in a tiny apartment, I *really* understand your wife's concern. I feel a litle sick inside every time my toddler throws a temper tantrum and I think about my neighbors.
However, housing prices out here are such that you really should be considering townhomes. Families all over this area live in townhomes; it's what you have to do to afford property here, especially as a first-time buyer, unless you are very wealthy. Restricting your search to SFHs in that price range will severely limit your options.
ICF is within walking distance of the Vienna/Fairfax Metro station on the Orange Line, so getting public transportation there should be a breeze, if you want to go that route.
The DC Metro webpage can help you plan a route from any house you might be considering. Otherwise, the drive really shouldn't be too bad either from Centreville, Burke, or Woodbridge. Burke has great schools and is a very attractive, safe and family-friendly place, but most of the stuff on the market in that area is...townhomes.