There are many hiking trails to redwoods, including a trail that leads to an ancient redwood tree, estimated to be about 2,000 years old. For the specific ancient redwood hike: https://jacklondonpark.com/ancient-redwood-hiking-trail/
If you are looking for a geothermal pool to relax in, check out Morton's Warm Springs. We haven't been but could be fun to check out!