I’ve moved and have now done this commute a few times. I’ll resurrect my own dormant thread to pass along my thanks and share what I have learned and what works for me:
Short version is that I come close to the route suggested by viennabiker, but with some differences east of Rock Creek depending which direction I am going.
I didn’t find that taking Rock Creek park down to the I-66/TR bridge is worth it – it’s a longer trip, and I find the TR bridge to be the worst of all of the downtown river crossings (it’s the narrowest, traffic moves faster than other bridges, and the “barrier” is so laughably low that it would only serve to launch a rider who hits it into the middle of the travel lane). Also, I didn’t find the sometimes crowded Rock Creek Park MUP all that much preferable to staying on surface roads.
From Adams Morgan to Ballston, I take Florida down the hill to P street. It sucks that there’s no bike lane, but the downhill means you can generally stay at traffic speed, and in the mornings traffic is not crazy; I’ve never felt uncomfortable on that stretch. I cross Rock Creek on P, then follow the trail for a couple of blocks through Rose park to “O” street and then pick my way sort of at random along the neighborhood streets north of “M” until I pick up Prospect St at Wisconsin. This takes me to 34th ST and down to “M” just a half block east of the Key bridge — then Custis Trail to Ballston.
Ballston to Adams Morgan: Custis to Key Bridge (upstream side) and then walk or ride the sidewalk (depending on pedestrian traffic) on the north side of M to “Bank Alley” up to Prospect to Wisconsin. A half-block on Wisconsin to “N” and then pick my way back to Rose Park to P and across Rock Creek. This time I stay on P a couple of blocks almost to Dupont Circle — taking 20th to Q -it’s all bike lanes from here- and then New Hampshire to 17th into Adams Morgan. Sometimes I skip New Hampshire and just take Q all the way to 17th. Of note, the bike lane on 17th is designated as an “upstream” corridor opposite to the one-way car traffic, so you have to be careful and assume neither drivers nor pedestrians are expecting you to come from that direction. But it’s a quiet enough street that it feels fine.
Thanks again for the advice. I may start a separate thread looking for some good, low-stress leisure rides that pass through this part of DC.