You can use Key Bridge in addition to the TR to reach 66 from the District. You may not want to in the end, but it shouldn't be forgotten, nor in the grand scheme of things should Chain Bridge. Getting to and across any of them in rush hour will be something of a challenge, but it will probably pay to keep all of the options in mind. Unless you can afford the big bucks in east Georgetown or Kalorama, potential neighborhoods that are near Dupont might include West End and Logan Circle, but I think you'll end up having to dig around some to find an area that balances affordability and desire to be near Dupont with the necessity of getting to Reston and back everyday. The good thing (if there is one) about the morning rush in DC is that it starts later than in the suburbs. It's sneaking up on 7:30 here and the
trafficland TV cameras show both Connecticut and Wisconsin are open and moving freely. Still, I would guess that in the end, moving into the District would at least double the daily commuting time...