There’s a wonderful walking/biking/running path in Kentfield that runs along Corte Madera Creek from Bon Air Road at the east end to the bridge crossing at Kent Middle School on the west (where Stadium Avenue deadends).
Because it runs along the creek, and has marshes for a good ways on the other side, you’re really walking right through the middle of a nature area, with lots of egrets, ducks, geese, herons, gulls, etc., all around you.
The trail surface is paved, and is in excellent condition most of the way. There are pooper-scooper bag dispensers at either end, so it’s an easy choice for a dog-walking outing. There are also a number of park benches, drinking fountains and garbage cans so it’s really user-friendly and great for a relaxing outing away from traffic.