Discovery Trail is a 1.7 mile moderately trafficked loop trail located near Philo, CA. The trail is good for all skill levels and primarily used for hiking and walking.
While your visiting the wine country (and feeling like you need to metabolize some wine off), why would you not stop at Hendy Woods State Park? This loop includes Big Hendy Grove and the Discovery Trail. It's almost as good as Montgomery Woods in the same vicinity. It's grand "coastal" Redwood Trees.