China Hole Trail Loop is a 9.4 mile moderately trafficked loop trail located near Morgan Hill, CA that features beautiful wild flowers and is rated as difficult. The trail is primarily used for hiking, walking, trail running, and birding and is accessible year-round.
The essential Henry Coe Hike: 10 arduous miles through the park's demanding mountainous terrain. China Hole is one of the most popular destinations at Henry Coe State Park. Spring rains create a picturesque swimming hole at the confluence of two creeks, making the nearby backcountry campsite a prized locale for overnight outings. A day hike to China Hole is a perfect alternative if you hate to sleep on the ground but love to get your heart pumping under the California sun. You'll also descend along the Madrone Soda Springs Trail and the Mile Trail, which passes the decaying remains of an era when the springs were a major tourist attraction. Best time to go: spring, when the hills are green and the wildflowers are popping, and early summer, when it's warm enough to swim at China Hole. The water gets more dank as summer progresses -- the puddles remaining after July tend to reek.
I am not convinced that this hike has 2000' gain - if it does then it is pretty well disguised. That figure is mentioned in the map published by CA State parks, but from the topological, elevation at Park HQ is around 2600' and Cayote creek is around 1200'. We could add in a couple of hundred feet to account for rolling terrain, we'd still be about 400' short.
This is a helpful guide with some really nice pictures.