The trails are off of Santiago Canyon Road, about 1.25 miles north of Cooks Corner. To get there check out one of these three routes.
From the 55 freeway take Chapman east and go up and over the foothills. After about 5 miles Chapman will turn into Santiago Canyon Road (at Jamboree). Stay on Santiago Canyon Road for 11.5 miles. On your left you will see Modjeska Grade Road (about 2 miles past Modjeska Canyon Road).
From the 5 freeway take Jamboree north for 6 miles. At Chapman/Santiago Canyon Road turn right. Stay on Santiago Canyon Road for 11.5 miles. On your left you will see Modjeska Grade Road (about 2 miles past Modjeska Canyon Road).
From south Orange County at the 5 freeway take El Toro north for about 5.5 miles towards Cooks Corner (a small, dive bar/resturant with tons of motorcycles out front). This is the intersection of Santiago Canyon and Live Oak Canyon Road. Stay to the left (on Santiago Canyon) and turn right onto Modjeska Grade Road 1.25 miles later.
Park anywhere along the side of the road on the half mike up to the trail head. You cannot park at the top so park somewhere below.