The Redwood Grove in Brea’s Carbon Cayon Regional Park is an easy hike to take with the kiddos. While the grove is only 200-ish yards long it’s nice to see so many Redwoods in one spot without having to drive up to the mountains.
Antonovich Trail in San Dimas was a fun hike with the kids. A lot of shade, a nice stream, things to look at. Plenty of little spots to explore and teach the kids about.