Mornings I ride from house in NW to Friendship Heights Metro, get off at Shady Grove, bike to office in Gaithersburg
Evening, I reverse this, but sometimes get off at Bethesda Metro, and take CCT south to either River Rd or Mass, then to house. As others say, CCT is a crowded mess in evenings, but if you commit to a slow ride, it's peaceful. I'm glad to have MUP options for when I just don't want to deal with cars.
I ride a mile along 355 and it's sparsely populated as far as stores/places to stop, so cars zoom along at 40-60+ MPH. Crossing where I-370 dumps in sucks. I'm centered in the right through lane, but to my right is first the off-ramp lane, then the on-ramp lane. Traffic in the 2 left lanes is insanely fast. Oh well, it all works somehow