This Sunday as in father's day through Thursday or the next Sunday?
Glendora and Long Beach are about an hour apart... GMR (Glendora Mountain Road) is in, well, Glendora and Azusa area. Closer to long beach you could do Santiago over by Cook's Corner.
http://www.motorides.com/Santiago isn't marked on there but it's by the 241, a little north west of the marker for the Lake Elsinor route.