With regard to Temecula, I can provide a bit of help. I have two kids (7 & 5 now), and we bought our first starter house in Temecula in 2000. We moved to Charlotte, NC a year or so ago for work (insert redneck jokes here). And yes, we’re trying to move back to SoCal.
Temecula is a great community. When we moved there we really missed a lot of the infrastructure from San Diego, but it has grown greatly since that time. Below are my thoughts on a few things:
Schools. Vary, like any city, but overall not bad. We personally had our son in a private Christian school. There are actually several fairly reasonable private schools in Temecula if that is a consideration.
Family Friendly. Very. Lots of stuff to do as a family, and a lot of activities. We actually thought there to do as a family than there was when we lived in Scripps Ranch. It seems like the vast majority of people in Temecula / Murrieta have families, so there are a ton of sports and other things to do together. Side note: Lake Elsinore Storm minor league baseball is about the best sports value for families in SoCal.
Weather. I found the charts for “averages” kind of deceiving. Make no mistake, it gets HOT here in the summer. Maybe not Phoenix hot, but definitely “crap, I hate my black leather interior” hot.
Commute. It’s changed – for the worse – over the last few years. As SD got higher, everyone that couldn’t afford housing there bought in the IE. If you have to regularly commute down the 15 to Pendleton you will definitely spend some time in the car every day. And other than the Ortega Hwy, there’s really only one way in and out (okay, two if you count the 215, but who wants to go out there?).
Desert. Okay, so most of SoCal is a desert, but this area is definitely more arid than most of SD.
So if you are okay with hot summers (dry heat!), and traveling on the 15 when necessary, it’s a great community. My wife, kids and I loved it there, and would totally consider moving back to Temecula. More likely, though, we would look for a deal in the Rancho Bernardo area. Did I mention it was hot?
Oh, and I may be out of touch, but didn’t Fallbrook used to be a concentration for the klan? Maybe it has changed, but it used to be about as diverse as a bag of marshmallows.