Lower Tubbs Island Loop Trail is a 7.9 mile moderately trafficked loop trail located near Sonoma, California that features beautiful wild flowers and is rated as moderate. The trail is primarily used for hiking, walking, nature trips, and birding and is accessible year-round.
Great area with lots of bird watching opportunities. I drive Hwy 37 regularly and it's a beautiful area. Not sure about the bike rider review and people walking around in their underwear, but I would not consider that a worthy review. The description clearly says "The trail is primarily used for hiking, walking, nature trips, and birding and is accessible year-round." not "...biking only if you tolerate thorns."
I planned on mountain biking the path,but the thorns on the path concerned me,so did the guy walking around in his underwear,by his van.