Austin McInerny has ridden many parts of the Bay Area Ridge Trail, but the avid cyclist wants to find the hidden parts he feels need to be brought into the light.

McInerny, of Berkeley, launched that mission Friday with a five-day bike ride, which will go through Napa, Vallejo and Benicia.

He said the ride is meant to drum up public awareness and support of the ridge trail, which includes nearly 400 acres of protected open space for hikers, bicyclists and equestrians.

A board member of the Bay Area Ridge Trail, McInerny said he wants to get a better handle on segments that can be added to make the trail more continuous.

"It is such an asset to the Bay Area," McInerny said, of the trail, adding that the mission will be useful in contacting public and private entities for support.

First and foremost, the ride will help McInerny learn how easy or hard it is for cyclists to use the ridge trail. Currently, just 80 percent is open to bicyclists, he said.

McInerny will be accompanied by Yuri Hauswald, a writer from Petaluma, and Salt Lake City photographer Scott Markewitz.

The trio will start and finish in San Francisco's Presidio and use public transportation at various intervals where the trail is not yet developed or is inaccessible to bikers.

At night, the group will stay with friends along the way or return to McInerny's Berkeley home to sleep.

They began their ride Friday through Solano County, Vallejo and Benicia, riding south parallel to Interstate 80 through Fairfield and into Lynch Canyon, Hiddenbrooke and Benicia.

From Benicia State Recreation Area, the cyclists will head to the Benicia Martinez Bridge and cross on the bridge's new bike pathway before continuing south through Contra Costa County and San Jose.

The trio plan to chronicle their experiences for a bicycle-magazine article.

They will also post daily updates on Facebook through the Bay Area Ridge Council's page at www.facebook.com/ridgetrail?ref=ts.