Serrano Campgrounds, Big Bear Lake. Directions: From I-10 in Redlands, CA, take State Hwy 30/330 north to State Hwy 18 in Running Springs. Continue east on Highway 18 at Bear Dam. Go straight, do not cross Dam. Hwy 18 becomes Hwy 38 at Dam. Continue on 38 to Serrano Campground sign on right side of Hwy 38.