There is a great hiking trail in Arcadia that is easy to find. Nicknamed "Chantry Flats" is located heading north straight up the mountain on Santa Anita Avenue. You will drive up a windy road for a couple of miles maybe 3. Once you come upon a parking area, park your car. Obtain a pass for about $5.00. If there is no parking initially, you can park further up for $1.00. The start of the trail head is fairly easy to find. It travels downhill down a road. Once it flattens out, a dirt hiking trail is visible. A couple of other trails will veer off the main trail and it will be indicated. The main trail will end at a wonderful waterfall. It's not too long. Maybe a mile and half or slightly more (one way). Very scenic and lots of views of the streams along the way. One of the easier hikes in this area.
5K road race - starts in parking lot of Mall, goes through Arboretum and ends up on the inner training track at Santa Anita. Fun but crowded and a bummer of a run in rainy season. Not a personal best type of run but still worth the trip. Is run in April on the same day as the Santa Anita Derby
Enjoy a day at the track. there is a nice infield with a playground if you have kids. The stands were built in the 1920s and are quite pretty if the track itself is unrelentingly harsh on the horses. Morning workouts canbe watched from the stands and stable tours are available. Breakfast at the trackside is available sometimes even when there is no racing. check website for details.