There is no through road across Pinnacles National Park, as the two sections of Highway 146 terminate either side of the central mountains, about 2 miles apart; a drive from the west entrance at the Chaparral Ranger Station to the (main) east visitor center in Bear Gulch is 60 miles along sometimes narrow, winding roads.
For trail descriptions, see the Pinnacles National Park hiking index
Nearby towns (with distances to Bear Gulch) include Coalinga (72 miles), King City (34 miles), Monterey (75 miles), Paso Robles (85 miles), and Salinas (61 miles).
PDF format maps of Pinnacles National Park, from the National Park Service:
(624 kb); detail map - High Peaks