Sempervirens Falls in Big Basin State Park is Temporarily Closed due to fires. More updates can be found at Parks.CA.Gov.
The hike to Sempervirens Falls is an easy 3.3 mile out-and-back hike on the Sequoia Trail. You'll travel through the redwood forest and some of the campgrounds located in Big Basin State Park. The hike is pleasant but on occasion, you'll be too close to the road to feel like you're deep in the wilderness.
The falls themselves are nice and have a little viewing deck, but I would suggest going after rain so that you can get the full effect. If you happen to go after it rains you'll also have the chance of running into a banana slug! The University of California at Santa Cruz's Mascot and an incredibly intriguing slug at that.