Welcome to BP Matt. I am also new to the forums and there is a lot of valuable information on here. I am in a similar position to you. I bought my first house over a year ago in DC and I live in it while renting out 2 rooms. I am in the process of locking down my second rental property in the city. Similarly, I am working with the long-term buy and hold rental property strategy.
I think DC and the surrounding area is still a good investment despite the high prices. I say this because of the appreciation that is possible in the area, especially recently. There is obviously more risk when factoring appreciation into your returns but in the city I still think that it is possible. With that being said, it is extremely to hard to find good investments in the city. The low inventory and rapid appreciation has made it harder, but there are still deals to be found.
If you haven't already I would recommend setting some keyword alerts for "dc" "dmv" and things like that so you can get notifications whenever someone posts about the area.