I'll be going to Murrieta California. It's not a bad location, still nice and warm, even closer to the beach than my first choice (Sacramento). It's pretty outside the city though which is the main down side. And, not as much as far as hiking goes in that area.
There are hidden gems that are accessible from Murrieta, including hiking trails, mountains, lakes, campgrounds, mountaineering, sky diving, wine country trips, with lots of wine tasting spots in the Temecula wineries/vineyards, plus different festivals and concerts.
@Barkley13 is correct about other places to visit because San Diego County (Sea World, San Diego Zoo, San Diego Safari Park, Joshua Tree National Park, and beaches), and Orange County (Disneyland, California Adventure, Knott's Berry Farm, Aquarium of the Pacific, state and regional parks and more beaches), and Los Angeles County (Magic Mountain, Universal Studios, museums, LA Zoo, beaches, music concerts, stage and theatre performances, galleries) are also accessible in about an hour.
One of my favorite places to visit when I go to San Diego County is the "San Diego Safari Park." It's part of the San Diego Zoo Wildlife Alliance. You can look it up on google. In addition to enjoying the sights of thousands of wild animals roaming free, it also offers overnight safaris and flightlines, among other things. If you attend an overnight safari, you will be blissfully awakened the following morning by the sounds of roaring lions.
Just my thoughts.