Definitley agree with @BatmanTheElf - riding to DC via the C&O is a low stress, low logistical bikepacking trip.
The W&OD is also great - start in Georgetown on the Custis trail towards Arlington and it connects all the way out to Purcellville, VA. Even better, you can make a loop from DC to Leesburg, VA via the W&OD, then take the Ferry at White's Ferry back into Maryland and connect to Rock Creek back down to the city.
Despite the traffic, politics, crowds, etc. DC is one of the best biking areas I've ever lived!
@trailbeard Thanks so much! I'm going to check out the W&OD when I have a little extra time. Have you been down south on the Virginia Capitol Trail? I'm wondering if they are similar with the paved path off the main road?
Anacostia River Trail! It's great for visiting Bladensburg Waterfront Park (also the cheapest kayak rentals around DC), Kenilworth Aquatic Garden, Anacostia Park, RFK, Navy Yard, all the way down to Nats Park and the Wharf. Most of it is separate from the road, safe, and very easy to follow.
You can also take the Anacostia River Trail north towards College Park vía the Northwest Branch’s Trail. It’s an easy, great ride with plenty of foliage and a scenic lake near the end.
Mt. Vernon trail IS great! I frequent the MBT (Metropolitan Branch Trail) and have found it to be a great connector and widely used by DC commuters.