Balanced Rock via Sandstone Trailhead leads you along the trail to 2 amazing boulder formations while enjoying epic views of the Santa Monica Mountain range throughout the whole hiking trail. You may even witness rock climbers climbing "Echo Cliffs'' just below Balanced Rock.
...From the PCH, make a left turn on Yerba Buena road (turn right if you're coming South) for about 6 miles until you get to the dirt parking area. If the lot is full, there's extra parking on the side of the road.
FYI, Balanced Rock can also be accessed by starting at the Mishe Mokwa trailhead, which is .4 miles up the road. I've started from both trails in the past, but I find Sandstone Peak trailhead to be more inspiring and scenic, so that's where I prefer to start.
On your way to Balanced Rock, you'll pass a sign that reads Sandstone Peak. If you have the extra time and want to reach the highest elevation point in all the Santa Monica Mountains (which sits at 3,111 ft), then make the 1,075 ft. elevation trek to the top. If not, continue on the trail until you get to the Sandstone Peak/Mishe Mokwa junction. Take the Mishe Mokwa trail for about a 1.5 miles till you get to Split Rock. If you're lucky, you may even witness some rock climbers ascending a vertical rock cliff known as "Echo Cliffs". This is a pretty popular spot for mountain climbers.
Once arrived at Split Rock, take a break at the shaded picnic area that's offered for the hikers usage. Don't forget to capture some pictures of the awesome super-sized boulder that's split in three's. When done, take the trail to the right to Balanced Rock. The trail is not as well maintained as the trail leading to Split Rock, so prepare for some scrambling through the brush. Hike the Balanced Rock trail for 0.3 miles till you get to the mighty unbalanced rock! Hard to get a full appreciation of the rock from the distance, so seeing it up close and personal is pretty amazing. Almost seems like with one good gush of wind it'll send this rock tumbling...haha!
When finished, head back the same way you came. Again, if you have more time, you can make the full loop, which will take you back to the start of the trailhead for a total of 6.2 miles.
Enjoy, be safe, and happy trails!