For a nice hike that offers up some challenging spots and good elevation gain but is also easily accessible from the Pasadena area, the Inspiration Point Interpretive Site is a great destination. This post routes the trail from Echo Mountain to Inspiration Point via the Castle Canyon Trail.
The Sepulveda Basin Wildlife Reserve is part of the 2000-acre Sepulveda Basin Recreation Area, which is a flood control basin turned recreation area. This reserve is a stop for many migratory birds along the Pacific Flyway and is a great place for bird-watching.
The historic Arroyo Seco Parkway is wonderfully scenic, taking drivers from wooded suburbs of South Pasadena to the rolling hills around Chavez Ravine to the bright lights of Downtown Los Angeles. There are also many points of interest- from sports venues to museums and cultural centers- along the way.
Echo Mountain is a popular front range hike with easy access from Altadena. At 5.5 miles round trip with about a 1400 foot elevation gain, it is considered moderate. There are some cool ruins at the top, harkening back to the 'Golden Age of Hiking."
There are many trails in the Angeles National Forest. Popular hikes in the Chantry Flats area take hikers to various pools and waterfalls. Bears are a common sight along the trail, so remember to be bear aware and recreate responsibly.
The Cranky Camper 