My husband does this commute everyday
From close in McLean (right over border about 5 mins from Country Club hills) it takes him 25 mins.
When we lived in Arlington...close to Ballston it took 35 mins.
I have noticed that there was more variability in his commute times from Arlington than from where we are in McLean (66 is less predictable than 123 for the reverse commute I guess)
You may want to consider close in McLean (22101) -lots of neighborhoods there...