Using CLIPR2, you're usually between 5,000 and 7,500 feet when you pass DC. As noted above, depending on the traffic at DCA, you might do your baseline turn as quickly as the Wilson Bridge, most commonly near Fort Washington, or significantly further down the river as far as La Plata.

FWIW, this approach isn't always done when coming out of the northeast. When NYC is very congested, flights from New England will often fly off the coast and cross over the Eastern Shore. This is known as the "DEALE3" arrival approach.

This is a relatively common approach when you're flying in from the Northeast (Philadelphia, JFK, Laguardia, Boston, Providence, Hartford, etc.). Flights are landing and taking off from Reagan on runway 1 as the wind is out of the north/northwest/northeast - much more common in fall and winter.

Aircraft continue south past DC, and depending on the flight patterns, traffic, and congestion, will do a 180 degree turn to line up with the main runway - sometimes as quick as the Wilson Bridge and sometimes as far south as La Plata. Fort Washington is a very common turn point.

This is known as the "CLIPR2" approach.

Ive taken it. Its about 57 minutes from Farragut West. Eastern Market - add an additional 13 minutes. You're actually looking at 70 minutes door to door.

Remember its a decent length walk from the Dulles station to the terminal. Add 6 minutes to that.

spothero.com works. Depending on your flight times and how much baggage you have, I'd definitely consider Metro though.