I was first introduced to the concept of "regional trails" (relatively long-distance paths, closed to car traffic, through the parks in cities and suburbs) by the Iron Horse trail running through Walnut Creek, which I walked along frequently and with gusto!
The San Francisco Bay Trail is an ambitious effort to connect 500 miles of trails around the San Francisco Bay Area. Many of my colleagues bike along it to work, and I'm lucky enough to walk along it on my way home from work.
The Santa Rosa creek trail is a beautiful path along a creek through a green belt in downtown Santa Rosa, and is also part of a larger trail network.
In case any civic planners, or folks voting on regional trail issues, are reading this, I'm a big fan of the concept and grateful for the existing trails 👍