The Crosstown Trail is a new route across San Francisco. Be one of the first to bike across it! See parts of the city you probably have not seen before.
This is true “mixed terrain”–some trails (mostly mild), roads ranging from freshly paved to not-so-freshly-paved, and paved pathways. There’s even some stairways, though there are always alternates to avoid the stairs.
Distance is about 17 miles and just over 2000′ of elevation gained.