A few months ago, I started working on a few bike tour routes reaching into D.C.’s suburbs, towards points of interest in urban planning history or just boozy destinations (and, even better, places with both). I’ll try to continue updating this map, but here are the completed and under-construction routes (the latter marked with POIs, but not connected yet):
- Wine, spirits, and beer in Alexandria & Mount Vernon
- Route 1 in Maryland: streetcar suburbs (Brookland, Hyattsville, Riverdale Park, College Park) and Greenbelt
- Montgomery County Agricultural Preserve to Purcellville distillery (back on W&OD)
- National Capital Streetcar Museum via Rock Creek trails
- Falls Church, Merrifield, old & new Reston via W&OD
- South Arlington redevelopment sites
- Columbia & Ellicott City
- Rockville & Gaithersburg
I’m aiming to present a few of these as guided tours, depending on whether I can find good tour guides at the POIs. Let me know if you can help.
west north 
Nice list. I’m glad to see a tour going to the National Capital Trolley Museum.
I’m surprised you didn’t include the Capital Crescent/Georgetown Branch trail, which goes through Bethesda and Silver Spring (sort of). Maybe it’s played out, but there are always people who are new to the area and may not know about the fight over the trail and the Purple Line. There’s also a fairly extensive trail network in the City of Rockville, which is a great opportunity to see some of the historic neighborhoods in the West End and Rockville Town Square.