Agree with all the recommendations given - there's plenty to see!
Big Bear isn't bad, as long as you know about leaning for takeoff at high airfields. Catalina is definitely tricky, and not for the faint hearted.
Sedona is fabulous.
My favourite of all time is the Grand Canyon. You need the special chart, but you can fly along much of the Canyon, and then drop into the airfield and take a short bus ride to the rim.
It really is a delightful place to fly. And some of the aircraft museums are fabulous, if you like that sort of thing. I did Santa Monica and Palm Springs, and spent a day at each.