San Juan Capistrano is 15 minutes from San Clemente and a fun historic place to visit. The Mission chapel is a historic landmark and museum and known as the Birthplace of Orange County. Known for the return of the swallows. Stand in line for the BBQ across the street from the Mission chapel!
Not a strenuous hike, it is uphill, but once you get to the "top" the views are incredible and 100% worth it. You will park on West Street off Pacific Coast Highway. Also find your way to West Street Beach - 192 steps down to the ocean (and also back up!)