Best hiking trails for 3-year-olds in Southern California?

Looking to get my toddler outside more on weekends. He can walk about a mile before getting tired, so nothing crazy. Needs to be something scenic enough that I don't completely lose my mind, lol. We're in the San Diego area. Anyone have go-to spots that won't end with me carrying a 35-lb kid for the last half mile? (Although let's be real, that might happen anyway.)