I live in Long Beach and love to head up the 605 to the hills above historic Uptown Whittier. Google Maps will show you several interconnecting trails in those hills. There are several trail heads in Whittier, La Habra Heights and Hacienda Heights. One that comes to mind is a trail head in Whittier on Greenleaf just north of the Uptown district. Depending on the trail, you can get views of the southern LA basin and OC, the westside and the West San Gabriel Valley.
You can also stop and check out Tricky Dick's alma mater, Whittier College.