Great loop hike from the parking lot to the campground and back. In warm weather, take the Saratoga Gap trail out and the Ridge trail back. The lower Saratoga trail is more exposed and has more difficult bits, and then you can return on the much shadier Ridge trail. The entire trip is 5.5 miles, but you shorten it at the Interconnect trail if you run out of steam. Just walking out the Ridge trail to Goat Rock is worth the trip! There are rugged parts requiring a bit of a scramble, so wear sturdy shoes (we wore hiking boots) and take water. Don't count on fog to keep you cool in summer. I recommend a day pack or the like so you can have your hands free.
Don't be intimidated by all the cars parked at the trailhead. Even on a busy day the trail isn't overly crowded after the first half mile.