Julie, I don't know much about orange county but I'm located north of you in San Francisco.
In terms of location, you cant ask to live in a better place than California as there is contrast in both landscape as well as climate type. When I first moved back to the bay area from Orlando I troubled myself with the same question regarding locations to shoot. One thing I have found that has worked well for me is simply taking a drive and wandering the area, finding parks and scoping them out ahead of time so when you are shooting you have an idea of where you want to go next.
Another thing i've noticed is that areas that are "touristy" or draw visitors usually seem to also be awesome locations for shoots, for example in my area the golden gate bridge or some of the museums make awesome backgrounds and allow alot of contrast and posing help.
Good luck in the golden state 