I'm looking for the same thing. I like the Oxon Hill club for rides in southern Maryland, but have not found something I'm completely happy with for Virginia rides.
The Reston Bike Club only has fast rides on weekends. They do have average-slower speed rides on weeknights, but I can't attend those.
Potomac Pedalers has lots of rides, but lately the internal politics has been annoying me, and their new website is a pain in the a$$ to deal with. That being said, I think their C and D rides are generally friendly. My experience with the CC rides is that I'm often dropped by almost everyone at the start, because most of the riders who show up are actually B or faster. Also, they don't have many rides starting in Reston/Herndon/Sterling, but places like Leesburg, Purcellville, Middleburg and Warrenton are not too far away and the scenery is usually worth the drive.
The Bike Lane has a group ride in Reston/Herndon/Oakton on Saturday mornings, but it's at a 17-18 mph pace, which is too fast for me.
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles