I am with those who suggest you rent for a while and then vist various areas to buy, unless you have a lot of time before you move down there to look at areas down there, which I have been doing now for 9 months. But the cost of those house hunting trips do add up.
If your kids are under 4, seems you can afford at least one more move before you want them settled in a school district.
As for areas, it is SD. Anywhere in SD is better than anywhere else that is not SD. I have lived in Carmel Valley and Del Mar and loved both. Yes, Del Mar is heaven on earth. CV has the best schoold district in the SD area and closest commute to Sorento Valley. It is definately an uberfamily community. Just don’t cross the street without looking out for a soccer mom on a mission.